,,bureau ,,( ,,economic ,,geology ,! ,univ]sity ( ,texas ,au/91 ,texas ,pet] ,t4 ,flawn1 ,director ,guidebook #f ,,texas ,,rocks ,,& ,,m9]als ,an ,amateur's ,guide ,by ,,roselle ,m4 ,,gir>d ,sket*es by ,bill ,m4 ,h>ris ,febru>y #aifd ,second ,pr9t+1 ,april #aigb ,?ird ,pr9t+1 ,april #aigf ,f\r? ,pr9t+1 ,may #aigi ,cont5ts ,page ,preface vii ,introduction #a ,e>?'s out] cru/ #b ,geologi/s #b ,"t & rock units #b ,geologic map #f ,:at are rocks & m9]als8 #g ,*emical elem5ts #g ,m9]als #g ,rocks #h ,igne\s rocks #i ,extrusive or volcanic igne\s rocks #i ,intrusive igne\s rocks #i ,s$im5t>y rocks #aj ,soils #aj ,s$im5t>y rock mat]ials 9 brok5 fragm5ts #aa ,s$im5t>y rock mat]ials 9 solution #ab ,cem5t+ mat]ials & *emical s$im5ts #ab ,s$im5t>y rocks =m$ by plants & animals #ab ,metamorphic rocks #ab ,/atic metamorphism #ac ,contact metamorphism #ac ,dynamic metamorphism #ad ,occurr5ce & prop]ties ( m9]als #ad ,h[ m9]als occur #ad ,cry/all9e m9]als #ad ,cry/als #ad ,imp]fect cry/als #ad ,amorph\s m9]als #ae ,"s di/+ui%+ prop]ties ( m9]als #ae ,color #af ,lu/] #af ,transmission ( light #af ,h>dness #af ,/reak or p[d] #ag ,cleavage #ag ,p>t+ #ag ,fracture #ag ,specific gravity #ah ,eff]vesc5ce 9 acid #ah ,"s special occurr5ces ( m9]als #ah ,cave deposits #ah ,concretions #ai ,geodes #ai ,petrifi$ wood #bj ,collect+ rocks & m9]als #bb ,rock & m9]al id5tification *>ts #bd ,h[ to use ! m9]al id5tification *>ts #bd ,key to m9]al id5tification *>ts #be ,m9]al id5tification *>ts #bf ,h[ to use ! rock id5tification *>ts #ci ,rock id5tification *>ts #dj ,descriptions ( "s ,texas rocks & m9]als #dc ,anhydrite #dc ,asbe/os #dc ,b>ite #dd ,basalt #de ,calcite #df ,cassit]ite #dg ,cele/ite #dh ,c9nab> #di ,clay #ea ,copp] m9]als 7*alcocite1 *alcopyrite1 mala*ite1 azurite7 #eb ,dolomite #ed ,feldsp> #ee ,fluorite #ef ,gal5a #eg ,g>net #eh ,gneiss #ei ,gold #ei ,granite #fa ,graphite #fb ,gypsum #fc ,halite #fe ,hematite #ff ,lime/one #fh ,limonite #gj ,llanite #ga ,magnetite #gb ,manganese m9]als 7braunite1 holl&ite1 pyrolusite7 #gc ,m>ble #ge ,mica #gf ,obsidian & vitrophyre #gg ,opal #gh ,pegmatite #gi ,pyrite #hj ,qu>tz #ha ,qu>tzite #hd ,rhyolite #he ,s& & s&/one #he ,s*i/ #hg ,s]p5t9e #hg ,%ale #hh ,silv] m9]als 7arg5tite1 c]>gyrite1 native silv]7 #hi ,sulfur #ij ,talc & soap/one #ic ,topaz #id ,t\rmal9e #id ,uranium m9]als 7c>notite1 uranophane1 pit*bl5de7 #ie ,volcanic a% 7pumicite7 #ig ,composition1 h>dness1 & specific gravity ( "s ,texas m9]als #ii ,books ab\t rocks & m9]als #ajj ,nonte*nical books = beg9n]s #ajj ,textbooks & o!r ref]5ce books #ajj ,select$ ref]5ces on ,texas rocks & m9]als #ajj ,gloss>y #ajb ,index #ajd ,illu/rations ,page ,guadalupe ,peak & ,el ,capitan 9 ! ,guadalupe ,m\nta9s1 ,culb]son ,c\nty1 ,texas #a ,e>?'s out] cru/ #b ,geologic "t scale #c ,g5]aliz$ geologic map ( ,texas #d-e ,a m9]al is made up ( *emical elem5ts #g ,a rock is made up ( m9]als #h ,extrusive igne\s rocks =m at ! e>?'s surface #i ,intrusive igne\s rocks =m b5ea? ! e>?'s surface #aj ,soils develop f wea!r$ rock & associat$ organic mat]ial #aa ,conglom]ate f ,webb ,c\nty1 ,texas #aa ,precipitat$ s$im5ts l9+ a teakettle #ab ,contact metamorphism #ac ,a scal5oh$ron #ad ,b>ite specim5 %[+ radial =m #ae ,*alc$ony %[+ botryoidal =m #af ,transp>5t m9]al #af ,/reak plate #ag ,con*oidal fracture #ah ,/alactites & /alagmites 9 ! ,cav]ns ( ,sonora1 ,sutton ,c\nty1 ,texas #ai ,calcite geode f ,travis ,c\nty1 ,texas #bj ,petrifi$ wood f ,texas ,gulf ,coa/al ,pla9 #bj ,prospector's hamm] #bb ,h& l5s #bb ,physiographic outl9e map ( ,texas #db ,massive anhydrite #dc ,amphibole asbe/os f ,gillespie ,c\nty1 ,texas #dd ,b>ite cleavage fragm5t f we/ ,texas #dd ,basalt f ,brew/] ,c\nty1 ,texas #de ,calcite has p]fect rhomboh$ral cleavage #df ,calcite cry/als 7dog-too? sp>7 f ! ,t]l+ua area ( ,brew/] ,c\nty1 ,texas #dg ,cele/ite cleavage fragm5t f ,lampasas ,c\nty1 ,texas #dh ,c9nab> & calcite cry/als f ! ,t]l+ua area ( ,brew/] ,c\nty1 ,texas #ej ,b5tonite is us$ z a drill+-fluid additive #ea ,hazel copp]-silv] m9e1 ,culb]son ,c\nty1 ,texas #ec ,dolomite rock f ,burnet ,c\nty1 ,texas #ed ,feldsp> cleavage fragm5t f ,llano ,c\nty1 ,texas #ee ,microcl9e feldsp> cry/als f ,llano ,c\nty1 ,texas #ef ,fluorite has octah$ral cleavage #eg ,gal5a has p]fect cubic cleavage #eg ,g>net cry/al =ms #eh ,gneiss f ,blanco ,c\nty1 ,texas #ei ,plac] gold 9 /ream gravels #fj ,granite f ,gillespie ,c\nty1 ,texas #fa ,texas ,/ate ,capitol build+ at ,au/9 is made ( ,burnet ,c\nty granite #fb ,graphite is us$ 9 p5cil lead1 g5]ator bru%es1 & lubricants #fc ,sel5ite gypsum cry/al f ,ba/rop ,c\nty1 ,texas #fd ,sel5ite gypsum rosettes f ,nolan ,c\nty1 ,texas #fd ,fibr\s gypsum f ,t]l+ua area1 ,brew/] ,c\nty1 ,texas #fe ,salt domes occur on ! ,gulf ,coa/al ,pla9 #ff ,specul> hematite f ,c>rizo ,m\nta9s1 ,hudspe? ,c\nty1 ,texas #fg ,lime/one f ,travis ,c\nty1 ,texas #fh ,lime/one qu>ry at ,georget[n1 ,williamson ,c\nty1 ,texas #fi ,limonite ore is *ang$ to metallic iron 9 a bla/ furnace #ga ,metallic iron is made into /eel 9 an op5-he>? furnace #gb ,magnetite1 ,llano ,c\nty1 ,texas #gc ,holl&ite f ,jeff ,davis ,c\nty1 ,texas #gd ,precambrian metamorphic m>ble f ,llano ,c\nty1 ,texas #ge ,mica m9]als h p]fect cleavage 9 "o direction #gf ,obsidian arr[heads #gg ,opaliz$ wood f ,wa%+ton ,c\nty1 ,texas #gh ,qu>tz-feldsp> pegmatite f ,burnet ,c\nty1 ,texas #gi ,pyrite ve9s 9 :ite m>ble f ,llano ,c\nty1 ,texas #hj ,cubic cry/als ( pyrite #hj ,qu>tz cry/al f ,burnet ,c\nty1 ,texas #ha ,ame?y/ geode f ! ,alp9e area ( ,brew/] ,c\nty1 ,texas #hb ,milky qu>tz f ,burnet ,c\nty1 ,texas #hb ,smoky-qu>tz cry/als f ,burnet ,c\nty1 ,texas #hc ,poli%$ agate f ,rio ,gr&e gravels ( ,zapata ,c\nty1 ,texas #hc ,jasp] f ,uvalde ,c\nty1 ,texas #hd ,s&/one f ,zavala ,c\nty1 ,texas #hf ,prospector #hi ,sulfur is obta9$ by ! ,fras* process #ib ,talc s*i/ f ! ,allamoore area ( ,hudspe? ,c\nty1 ,texas #ic ,topaz cry/al f ,mason ,c\nty1 ,texas #id ,black t\rmal9e cry/als ) milky qu>tz f ,llano ,c\nty1 ,texas #ie ,a ,geig] c\nt] is us$ to detect radioactivity #if ,,preface ,?is booklet has be5 design$ to s]ve z a brief1 simple guide t w be ( help to s*ool *ildr51 amateur collectors1 & o!rs :o are j beg9n+ to develop an int]e/ 9 ! rocks & m9]als ( ,texas4 ,x is a companion volume to ,texas ,fossils by ,william ,h4 ,mat!ws ,,iii publi%$ z ,guidebook ,no4 #b by ! ,bureau ( ,economic ,geology4 ,num]\s pres5t & =m] /aff memb]s ( ,! ,univ]sity ( ,texas contribut$ "t & tal5ts to ! prep>ation ( ?is book1 & _! help is gratefully ackn[l$g$3 ,pet] ,t4 ,flawn1 ,director ( ! ,bureau ( ,economic ,geology1 ,?omas ,e4 ,br[n1 ,john ,w4 ,dietri*1 ,alan ,humphreys1 ,elb]t ,a4 ,k+1 ,jr41 ,pet] ,u4 ,rodda1 & o!rs1 includ+ ! late ,john ,t4 ,lonsdale1 made _m helpful sugge/ions2 ,john ,s4 ,h>ris & ,miss ,joseph9e ,casey edit$ ! manuscript2 ,cad] ,a4 ,%elby prep>$ a numb] ( ! photographs2 ,bill ,m4 ,h>ris made ! illu/rative sket*es "u ! direction ( ,james ,w4 ,macon2 & ,cyril ,satorsky design$ ! cov]4 ,texas ,rocks & ,m9]als ,an ,amateur's ,guide ,roselle ,m4 ,gir>d ,,introduction ,texas has a great v>iety ( rocks & m9]als--"s are common & o!rs are n4 ,?is book is design$ to acqua9t y ) "s ( !m & to tell y 9 a nonte*nical way :at !y are l1 "s ( ! places :]e !y are f\nd1 & h[ !y are us$4 ,al?\gh we d n "k exactly h[ all ( ! rocks & m9]als =m$1 "s ( ! ideas ab\t _! orig9 are m5tion$4 ,if y w\ld l to le>n m ab\t rocks & m9]als 9 g5]al1 ! names ( sev]al ref]5ce books are li/$ on page #ajj4 ,9 addition1 sci5tific reports t describe 9 detail _m ( ! rocks & m9]als ( ,texas h be5 publi%$ by ! ,bureau ( ,economic ,geology ( ,! ,univ]sity ( ,texas1 ! ,unit$ ,/ates ,geological ,survey1 & o!r organizations4 ,a select$ li/ ( ^! reports is giv5 on pages #ajj-aja4 ,rocks & m9]als are famili> objects to all ( u4 ,we pick up attractive or unusual pebbles = our collections1 we admire rocky m\nta9 peaks1 we speak ( ! m9]al res\rces ( our ,/ate & ,nation4 ,rocks & m9]als ent]1 ei!r directly or indirectly1 into our daily liv+4 ,f !m come ! soils 9 :i* gr[ ! gra9s1 ! fruits1 & ! vegetables = our food1 ! trees = our lumb]1 & ! fl[]s = our pleasure4 ,! iron1 copp]1 lead1 gold1 silv]1 & manganese1 ! sulfur & salt1 ! clays & build+ /ones1 & ! o!r metals & nonmetals t we require = our way ( liv+ 7 once a "p ( ! e>?'s cru/4 ,illu/ration3 ,texas' highe/ m\nta9 is ,guadalupe ,peak1 "r1 ) an elevation ( #h1gea feet4 ,el ,capitan1 left1 has an elevation ( #h1jgh feet4 ,^! peaks 9 ! ,guadalupe ,m\nta9s 9 ,culb]son ,c\nty consi/ l>gely ( ,capitan reef lime/one1 :i* =m$ dur+ ! ,p]mian ,p]iod4 ,e>?'s ,out] ,cru/ ,rocks & m9]als make up mo/ ( ! out] lay] or cru/ ( our e>?--! actual gr\nd b5ea? our feet4 ,! cru/ is approximately #ah to #cj miles ?ick b5ea? ! cont95ts4 ,9 g5]al1 ! out]mo/ "p consi/s ( _m lay]s ( /ratifi$ rocks1 "o above ano!r4 ,! old] rocks normally make up ! bottom or ! deep] lay]s1 & ! y\ng] rocks =m ! upp] lay]s4 ,n all ! lay]s are p]fectly flat & p>allel--"s are l5ticul> 7l5s-%ap$71 "s are tilt$1 "s are p>tly erod$ away1 & "s are pres5t 9 "o place & abs5t 9 ano!r4 ,b5ea? ! cont95ts1 ! lay]s ( rock re/ on anci5t metamorphic rocks & on great masses ( igne\s rock su* z granite4 ,^! l[] rocks are kn[n z ! basem5t4 ,illu/ration3 ,e>?'s out] cru/ 7?ickness n drawn to scale74 ,ov] mu* ( ! l& surface ( ! e>?1 ! out]mo/ lay] is made up ( lay]s ( rock ,on ! cont95ts1 ! lay]s ( rock re/ on metamorphic rocks & on igne\s rocks su* z granite ,geologi/s ,^? :o /udy ! e>?'s cru/--its orig91 hi/ory1 rocks1 m9]als1 fossils1 & /ructure--are kn[n z geologi/s4 ,! geologi/s :o are especially int]e/$ 9 a p>ticul> phase ( geology1 z ?is sci5ce is call$1 are giv5 special names3 ^? :o /udy fossils are call$ paleontologi/s2 ^? :o /udy m9]als are call$ m9]alogi/s2 ^? :o /udy rocks are call$ petrologi/s4 ,"t & ,rock ,units ,! e>?'s cru/ is believ$ to be at lea/ #c billion ye>s old4 ,9 ord] to deal ) ?is va/ /ret* ( "t1 geologi/s h divid$ ! billions ( ye>s into v>i\s "t units & h giv5 ea* unit a "n4 ,! great divisions ( geologic "t1 call$ eras1 are ,e>ly ,precambrian1 ,late ,precambrian1 ,paleozoic1 ,mesozoic1 & ,c5ozoic4 ,^! eras are divid$ into small] units ( "t call$ p]iods1 & ! p]iods are divid$ into epo*s4 ,! xx "t scale %[s ! geologic "t divisions4 ,e>lie/ geologic "t is %[n at ! bottom ( ! scale2 mo/ rec5t is %[n at ! top4 ,by exam9+ & /udy+ ! diff]5t rocks & rock lay]s1 geologi/s try to discov] 9 :i* unit ( geologic "t ^! rocks =m$4 ,^? rocks t =m$ dur+ a p]iod ( geologic "t are call$ a sy/em ( rocks2 ^? t =m$ dur+ an epo* are call$ a s]ies4 ,= example1 ! ,cambrian ,sy/em ( rocks =m$ dur+ ! ,cambrian ,p]iod2 ! ,cretace\s ,sy/em ( rocks =m$ dur+ ! ,cretace\s ,p]iod2 ! ,t]ti>y ,sy/em ( rocks =m$ dur+ ! ,t]ti>y ,p]iod4 ,we are n[ 9 ! y\ng] epo* 7call$ ,rec5t7 ( ! ,quat]n>y ,p]iod ( ! ,c5ozoic ,era4 ,! rocks t are =m+ n[ are ! ,rec5t ,s]ies ( rocks4 ,illu/ration3 ,geologic "t scale ,,era ,,p]iod ,,epo* ,,c5ozoic ,,quat]n>y 7la/$ #j-a million ye>s7 ,rec5t ,plei/oc5e ,,t]ti>y 7la/$ #fb million ye>s7 ,plioc5e ,mioc5e ,oligoc5e ,eoc5e ,paleoc5e --#fc million ye>s ago-- ,,mesozoic ,,cretace\s 7la/$ #gb million ye>s7 ,,jurassic 7la/$ #df million ye>s7 ,,triassic 7la/$ #di million ye>s7 --#bcj million ye>s ago-- ,,paleozoic ,,p]mian 7la/$ #ej million ye>s7 ,,p5nsylvanian 7la/$ #cj million ye>s7 ,,mississippian 7la/$ #ce million ye>s7 ,,devonian 7la/$ #fj million ye>s7 ,,silurian 7la/$ #bj million ye>s7 ,,ordovician 7la/$ #ge million ye>s7 ,,cambrian 7la/$ #ajj8 million ye>s7 --#fjj8 million ye>s ago-- ,,late ,,precambrian ,,e>ly ,,precambrian ,^! "t e/imates are f ! pap]1 ,geologic ,"t ,scale1 by ,j4 ,lawr5ce ,kulp1 publi%$ 9 ,sci5ce1 ,vol4 #acc1 ,no4 #cdei1 ,april #ad1 #aifa4 7,! "t divisions are n drawn to scale7 ,illu/ration3 ,plate #aj4 ,,g5]aliz$ ,,geologic ,,map ,,( ,,texas ,modifi$ f ,geologic ,map ( ,texas1 #aicc ,,explanation ,,c5ozoic #a ,quat]n>y #b ,t]ti>y 7,oligoc5e1 ,mioc5e1 & ,plioc5e7 #c ,t]ti>y 7,eoc5e7 #d ,volcanic 7extrusive7 igne\s rocks ,,mesozoic #e ,upp] ,cretace\s 7,gulf s]ies7 #f ,l[] ,cretace\s 7,coman*e s]ies7 #g ,jurassic #h ,triassic ,,paleozoic #i ,p]mian #aj ,mississippian & ,p5nsylvanian #aa ,cambrian1 ,ordovician1 ,silurian1 ,devonian & undivid$ ,paleozoic #ab ,rocks 7,precambrian7 old] ?an ,paleozoic #ac ,intrusive igne\s rocks 7,precambrian1 ,mesozoic or ,c5ozoic7 ,^! rocks are f\nd ei!r at ! surface or directly b5ea? ! soils & subsoils :i* cov] mo/ ( ,texas4 ,geologi/s also subdivide rocks into less] units4 ,"o ( ^!1 call$ a gr\p1 is made up ( two or m =mations4 ,a =mation comprises rocks or /rata 7lay]s ( rock7 t are recogniz$ & mapp$ z a unit4 ,"s =mations consi/ ( lay]s ( "o p>ticul> type ( rock1 su* z lime/one or %ale4 ,=mations are nam$ aft] a ne>by geographic locality1 & 9 "s =mation names1 ! type ( rock is includ$4 ,= example1 ?ree ( ! ,texas geologic =mations are call$ ,buda ,lime/one1 ,del ,rio ,clay1 & ,eagle ,=d ,%ale4 ,geologic ,map ,! geologic map 7pp4 #d-e7 %[s ! rocks t are f\nd at ! surface 9 ,texas4 ,"s ( ^! are extremely old4 ,"s1 geologically speak+1 are v "y4 ,,:at ,,are ,,rocks ,,& ,,m9]als8 ,al?\gh rocks & m9]als are (t5 m5tion$ toge!r1 & to "s p !y h simil> mean+s1 geologi/s make a di/9ction betwe5 ! two words4 ,9 g5]al1 rocks are made up ( m9]als1 & m9]als are made up ( *emical elem5ts4 ,*emical ,elem5ts ,! *emical elem5ts include oxyg51 silicon1 calcium1 sulfur1 c>bon1 gold1 silv]1 & _m o!rs4 ,!re are #ij naturally occurr+ elem5ts4 ,ea* is made up ( molecules t consi/ ( only "o k9d ( atom4 ,*emical elem5ts may ei!r be comb9$ ) ea* o!r or occur alone4 ,!y are ! build+ blocks ( our _w = !y make up all ! gases1 all ! liquids1 all ! m9]als1 all ! plant & animal life1 & all ! o!r physical matt]4 ,"s ( ! *emical elem5ts t occur 9 ! rocks & m9]als m5tion$ 9 ?is book are li/$ bel[4 ,alum9um ,al ,b>ium ,ba ,b]yllium ,be ,boron ,b ,calcium ,ca ,c>bon ,c ,c]ium ,ce ,*lor9e ,cl ,copp] ,cu ,fluor9e ,f ,gold ,au ,hydrog5 ,h ,iron ,fe ,lead ,pb ,magnesium ,mg ,manganese ,mn ,m]cury ,hg ,molybd5um ,mo ,oxyg5 ,o ,potassium ,k ,silicon ,si ,silv] ,ag ,sodium ,na ,/rontium ,sr ,sulfur ,s ,?orium ,? ,t9 ,sn ,uranium ,u ,vanadium ,v ,yttrium ,y ,z9c ,zn ,zirconium ,zr ,we c comp>e ! *emical elem5ts to ! lett]s ( our alphabet4 ,! lett]s1 l ! *emical elem5ts1 are fundam5tal build+ blocks1 & !y c be br\ght toge!r 9 v>i\s comb9ations to =m words4 ,m9]als ,a m9]al c be comp>$ to a ^w ( our language4 ,we comb9e lett]s to =m a ^w1 & nature comb9es c]ta9 *emical elem5ts to =m ea* p>ticul> m9]al4 ,= example1 calcite1 a m9]al t is abundant 9 ,texas1 is always made up ( ! same proportions ( ! same ?ree elem5ts3 calcium1 c>bon1 & oxyg54 ,illu/ration3 ,a m9]al is made up ( *emical elem5ts4 ,! m9]al calcite1 = example1 always consi/s ( ! same proportions ( calcium1 c>bon1 & oxyg54 ,ea* m9]al has its own *>act]i/ic int]nal /ructure & o!r prop]ties4 ,at ord9>y temp]atures1 ne>ly all ! m9]als are solids r ?an gases or liquids4 7,wat] & m]cury are ! pr9cipal exceptions47 ,9 addition1 m9]als are inorganic r ?an be+ compos$ ( plant or animal matt]4 ,:5 a s+le *emical elem5t is f\nd alone 9 nature z a solid1 x is consid]$ to be a m9]al1 too4 ,gold1 silv]1 copp]1 lead1 & sulfur are "s ( ! *emical elem5ts t c occur alone z solid m9]als4 ,:5 !y occur ?is way1 we ref] to !m z native silv]1 native copp]1 or native sulfur4 ,al?\gh ! elem5t m]cury is a liquid r ?an a solid at ord9>y temp]atures1 x too is a m9]al :5 x occurs alone 9 nature4 ,x is !n call$ native m]cury4 ,rocks ,we h already comp>$ ! *emical elem5ts to ! alphabet & ! m9]als to words4 ,we c n[ g a /ep fur!r & comp>e rocks to s5t5ces4 ,we put words toge!r to make s5t5ces2 nature puts m9]als toge!r to make rocks4 ,a s5t5ce does n h to be made up ( a def9ite numb] ( words1 nor does a rock h to be made up ( a def9ite numb] ( m9]als4 ,"s rocks1 su* z granite1 may be compos$ ( sev]al m9]als4 ,o!rs1 su* z dolomite & rock gypsum1 consi/ ( only "o m9]al4 ,m9]als d n lose _! id5tities :5 !y make up a rock4 ,in/ead1 !y are m]ely associat$ toge!r 9 v>y+ proportions4 ,"s rocks1 z we w f9d lat]1 in/ead ( be+ compos$ ( ! m9]als !mselves1 are made up ( fragm5ts ( e>li]-=m$ rocks4 ,ord9>ily1 we ?9k ( rocks z h>d & solid sub/ances1 su* z lime/one & granite1 b "s geologi/s consid] loose & uncem5t$ mat]ials1 su* z s&1 gravel1 or volcanic a%1 to be rocks also4 ,! words s$im5ts or deposits are (t5 us$ to describe ?is uncem5t$ or loose mat]ial4 ,rocks are commonly gr\p$1 accord+ to h[ !y =m$1 into ?ree great classes kn[n z igne\s1 metamorphic1 & s$im5t>y4 ,illu/ration3 ,a rock is made up ( m9]als4 ,! igne\s rock granite1 = example1 consi/s *iefly ( qu>tz & feldsp>2 o!r m9]als su* z mica & hornbl5de are commonly pres5t4 ,,igne\s ,,rocks ,igne\s rocks result f ! cool+ ( hot1 molt5 rock mat]ial or magma4 ,magma t rea*es ! surface ?r\gh volcanoes is call$ lava4 ,magma comes f deep )9 ! e>? & is made up ( a mixture ( molt5 m9]al mat]ials4 ,igne\s rocks h be5 =m+ ?r\gh\t ! geologic pa/ & are /ill =m+ today4 ,we c und]/& h[ !y =m :5 we look at pictures ( hot1 molt5 lava fl[+ f volcanoes1 su* z ,mauna ,loa 9 ,hawaii4 ,z lava cools1 x h>d5s into rock4 ,extrusive or ,volcanic ,igne\s ,rocks ,! igne\s rocks t =m on ! e>?'s surface are call$ extrusive or volcanic igne\s rocks4 ,:5 magma fl[s to ! surface1 x cools & h>d5s quickly4 ,! m9]al gra9s t =m dur+ ?is fa/ cool+ may be too small to be di/+ui%$ f ea* o!r4 ,"s lava cools too quickly = m9]als to cry/allize--!n ! rock is volcanic glass4 ,illu/ration3 ,extrusive igne\s rocks =m at ! e>?'s surface f lava t cools & h>d5s relatively quickly4 ,no volcanic igne\s rocks are =m+ 9 ,texas n[4 ,h[ev]1 dur+ ,t]ti>y "t1 9 ! ,big ,b5d area & 9 o!r p>ts ( ! ,trans-,pecos c\ntry ( we/ ,texas1 lava came to ! surface & h>d5$4 7,! physiographic outl9e map1 p4 #db1 %[s :]e ^! areas are locat$47 ,intrusive ,igne\s ,rocks ,! cool+ & h>d5+ ( hot1 molt5 magma also takes place bel[ ! e>?'s surface4 ,"h1 ! magma cools sl[ly to =m rocks made up ( m9]al gra9s t are l>ge en\gh to be readily visible4 ,^! rocks are kn[n z intrusive igne\s rocks4 ,we "k t !y are pres5t bel[ ! surface 9 ,texas because ( wells drill$ 9 _m areas ( ! ,/ate4 ,9 ,pecos ,c\nty1 a well rea*$ granite1 an intrusive igne\s rock1 at a dep? ( #af1eaj feet4 ,o!r wells 9 ,texas h rea*$ ! granite basem5t rocks at mu* %all[] dep?s4 ,b n all intrusive igne\s rocks 9 ,texas are f\nd und]gr\nd4 ,9 ! ,trans-,pecos c\ntry ( we/ ,texas1 9 ! ,balcones fault zone1 & 9 ! ,llano uplift ( c5tral ,texas1 "s are n[ se5 at ! surface4 ,!y1 l all intrusive rocks1 7 =m$ bel[ ! gr\nd1 b e>?'s processes ( uplift & erosion h gradually uncov]$ !m4 ,illu/ration3 ,intrusive igne\s rocks =m f molt5 rock mat]ial 7magma7 t cools & h>d5s b5ea? ! e>?'s surface4 ,,s$im5t>y ,,rocks ,s$im5t>y rocks are made up ( s$im5ts1 :i* are rock & m9]al gra9s t h come f wea!r$ rocks ( all k9ds4 ,rocks are wea!r$ :5 wat]1 ice1 sn[1 w9d1 & o!r ag5ts cause !m ei!r to dissolve1 z table salt does :5 put 9 wat]1 or to break ap>t1 z old pavem5t commonly does4 ,soils ,"s ( ! brok5-d[n rocks1 along ) associat$ plant & animal matt]1 develop into soils4 ,:5 y exam9e soil ) a magnify+ glass1 y may be able to see "s ( ! small rock & m9]al gra9s t /ill rema9 9 x4 ,"s soils h =m$ on top ( ! rocks f :i* !y came1 & "s h be5 mov$ 9 f ano!r place4 ,illu/ration3 ,soils develop f wea!r$ rock & associat$ organic mat]ial4 ,,soil ,,subsoil ,,wea!r$ ,,rock ,,b$rock ,s$im5t>y ,rock ,mat]ials 9 ,brok5 ,fragm5ts ,wat] & w9d n only wea!r ! rocks & soils b also move ! wea!r$ mat]ials 7! s$im5ts7 & deposit !m 9 o!r places4 ,:5ev] y see a du/ or s& /orm1 or a muddy creek or riv]1 y are obs]v+ ! movem5t ( s$im5ts by w9d & wat] to o!r l& areas or to ! sea4 ,! comb9ation ( wea!r+ & movem5t is call$ erosion4 ,illu/ration3 ,conglom]ate f ,webb ,c\nty1 ,texas1 is compos$ ( r\nd$ gravel t has be5 cem5t$ toge!r4 ,"s ( ! rock fragm5ts c>ri$ by wat] are /ill fairly l>ge :5 !y rea* _! de/9ations4 ,on ! basis ( size1 !y are call$ b\ld]s1 cobbles1 pebbles1 & granules4 ,loose deposits ( ^! l>g]-size s$im5ts make up :at is kn[n z gravel4 ,nature cem5ts gravels toge!r to =m rocks su* z conglom]ates 7made up ( r\nd$ gravel7 & breccias 7made up ( %>p-corn]$ gravel74 ,! f9] s$im5ts are call$ s&1 silt1 mud1 & clay4 ,:5 cem5t$1 ! s& gra9s become s&/ones1 ! silt p>ticles become silt/ones1 & ! mud & clay p>ticles become %ale4 ,! s$im5t>y rocks t are made up ( ^! rock fragm5ts are call$ cla/ic or fragm5tal rocks4 ,s$im5t>y ,rock ,mat]ials 9 ,solution ,z !y are wea!r$1 "s rocks dissolve & g into solution4 ,= example1 a numb] ( ! ,texas creeks & riv]s c>ry calcium c>bonate 9 solution because !y fl[ ?r\gh areas :]e lime/one rocks1 :i* consi/ mo/ly ( calcium c>bonate1 are be+ wea!r$4 7,wat] t conta9s a l>ge am\nt ( dissolv$ rock mat]ial is call$ h>d wat]47 ,cem5t+ mat]ials & *emical s$im5ts4-- ,"s ( ! wat]s conta9+ dissolv$ rock mat]ial seep ?r\gh loose s$im5ts :]e ! dissolv$ mat]ial may come out ( solution & =m a cem5t1 :i* b9ds ! s$im5ts toge!r4 ,= example1 :5 loose s& s$im5ts are cem5t$1 !y =m s&/one4 ,?ree ( ! mo/ common cem5ts are iron oxide1 calcium c>bonate1 & silicon dioxide1 al?\gh a numb] ( o!r mat]ials also s]ve z cem5ts4 ,dissolv$ rock mat]ials come out ( solution n only to s]ve z cem5t+ ag5ts b to =m ! *ief m9]al ( "s s$im5t>y rocks z well4 ,s$im5t>y rocks ( ?is k9d =m mo/ly 9 lakes & seas into :i* mu* dissolv$ mat]ial is c>ri$ by riv]s4 ,:5 ! dissolv$ mat]ial comes out ( solution1 x is said to be precipitat$ & ! m9]al s$im5ts x =ms are ! *emical s$im5ts4 ,"s lime/ones orig9ate ?is way4 ,y c see examples ( precipitat$ mat]ials by not+ ! cru/-l deposits t =m inside "s wat] pipes & teakettles1 z dissolv$ mat]ial 9 ! wat] comes out ( solution4 ,illu/ration3 ,precipitat$ s$im5ts are commonly obs]v$ l9+ a teakettle4 ,s$im5t>y rocks =m$ by plants & animals4-- ,! dissolv$ rock mat]ial c come out ( solution 9 ano!r way4 ,"s plants & animals are able to take dissolv$ calcium c>bonate out ( ! sea wat] & use x to build _! %ells & o!r /ructures4 ,"s ( ^! organisms1 su* z corals & algae1 c gr[ upw>d f ! sea floor 9 l>ge gr\ps to =m reefs t lat] become reef lime/ones4 ,o!r lime/ones are made up ( ! rema9s ( plants & animals t collect on ! sea floor & become cem5t$ toge!r4 ,,metamorphic ,,rocks ,metamorphic rocks come f e>li]-=m$ rocks t h und]gone a *ange or a metamorphosis4 ,all igne\s & s$im5t>y rocks1 & e>li]-=m$ metamorphic rocks too1 c be *ang$1 )\t be+ mov$ to "s o!r place1 into new & diff]5t rocks4 ,z !y are *ang$1 !y may become h>d]1 new m9]als may =m1 & !y may look entirely diff]5t4 ,= example1 granite1 an igne\s rock1 c be *ang$ into ! metamorphic rock kn[n z gneiss2 lime/one1 a s$im5t>y rock1 c be *ang$ into m>ble2 %ale1 a s$im5t>y rock1 c be *ang$ into slate4 ,^! *anges occur because ! e>? is a big & complex *emical sy/em4 ,! ag5ts t br+ ab\t ^! *anges1 :i* always occur bel[ ! surface ( ! e>?1 are heat1 pressure1 & fluids--bo? liquids & gases4 ,sev]al diff]5t k9ds ( *ange or metamorphism c take place4 ,/atic ,metamorphism ,"s ( ! *anges occur because ! rocks are at great dep?s4 ,z m & m y\ng] rocks are deposit$ on top ( !m1 ! old] rocks become deeply buri$4 ,! great ?icknesses ( y\ng] rocks are heavy1 & !y squeeze & press d[n on ! rocks b5ea? !m4 ,! deeply buri$ rocks are also hott] ?an surface rocks4 ,9 g5]al1 ! temp]ature increases ab\t #a ,fahr5heit = ea* #ej feet ( dep? bel[ ! surface4 ,! *ange ( deeply buri$ rocks into new rocks by pressure & heat is kn[n z /atic metamorphism4 ,contact ,metamorphism ,ano!r me?od ( *ange or metamorphism involves molt5 igne\s rock mat]ial4 ,:5 hot magma moves up ?r\gh rocks1 x n only heats & pu%es !m1 b x also may soak !m ) liquids & gases1 caus+ ! ne>by rocks to *ange into new rocks1 by a process call$ contact metamorphism4 ,illu/ration3 ,"s rocks are alt]$ by heat & fluids :5 !y are invad$ by hot magma 9 a process call$ contact metamorphism4 ,,unalt]$ ,,rock ,,metamorphic ,,rock ,,magma ,dynamic ,metamorphism ,/ill ano!r rock-*ang+ process is "o t is associat$ ) m\nta9 build+4 ,:5 m\nta9s are =m$1 heat & great pressures develop deep )9 ! e>?'s cru/4 ,! flat lay]s ( rock are !n sl[ly pu%$ & squeez$ s t !y b5d up into ar*es1 fracture1 or slide ov] ea* o!r4 ,^! =ces cause great *anges 9 ! rocks 9 widespread areas4 ,?is process ( *ange is kn[n z dynamic metamorphism4 ,occurr5ce & ,prop]ties ( ,m9]als ,,h[ ,,m9]als ,,occur ,rocks are made up ( m9]als4 ,9 addition1 m9]als are associat$ ) rocks 9 o!r ways4 ,= example1 m9]als fill or coat cracks & cavities t h develop$ 9 "s ( ! rocks4 ,m9]als are ei!r cry/all9e or amorph\s4 ,cry/all9e ,m9]als ,mo/ m9]als are cry/all9e4 ,9 cry/all9e m9]als1 comb9ations ( atoms are arrang$ 9 ord]$ patt]ns1 :i* are repeat$ ov] & ov]4 ,?is ord]ly int]nal /ructure ( atoms is a *>act]i/ic ( ea* cry/all9e m9]al1 z m9]alogi/s are able to det]m9e by us+ ,x-rays & special microscopes4 ,cry/als4-- ,:5 a m9]al occurs z a well-=m$ individual cry/al1 x has a def9ite1 precise %ape4 ,! k9d ( cry/al %ape x has dep5ds on its own type ( cry/all9e int]nal /ructure4 ,a well-=m$ cry/al has smoo?1 flat1 out] surfaces call$ cry/al faces1 :i* are arrang$ toge!r to =m prisms1 cubes1 pyramids1 & _m o!r geometric %apes4 ,= example1 qu>tz1 a common ,texas m9]al1 is commonly f\nd z a six-sid$1 prism-%ap$ cry/al t is topp$ by pyramid-l =ms4 ,pyrite1 ano!r common m9]al1 occurs z cube-%ap$ cry/als4 ,we c id5tify "s m9]als m readily by le>n+ to recognize _! cry/al %apes4 ,illu/ration3 ,a scal5oh$ron1 "o ( ! _m cry/al =ms ( calcite4 ,imp]fect cry/als4-- ,a cry/all9e m9]al commonly =ms "u conditions t d n p]mit x to become a well-%ap$ cry/al4 ,al?\gh ! m9]al may %[ a few cry/al faces1 x does n h a complete cry/al %ape & s is describ$ z massive1 or is said to occur 9 masses4 ,"s ( ! m9]als t make up rocks occur z cry/all9e masses4 ,= example1 calcite is a cry/all9e m9]al t occurs 9 ! metamorphic rock m>ble )\t its normal cry/al %ape4 ,_m cry/all9e m9]als occur z incomplete & imp]fect cry/als t are gr\p$ toge!r 9 v>i\s arrangem5ts4 ,if ^! incomplete cry/als are arrang$ ar\nd a common c5t] l ! spokes ( a :eel1 !y are said to be radial or radiat$4 ,if ! gr\ps ( incomplete cry/als look l bundles ( /r+s or fib]s1 !y are describ$ z fibr\s4 ,if !y are 9 r\nd$ masses t resemble bun*es ( grapes1 !y are call$ botryoidal4 ,if !y look l fi% scales1 !y are describ$ z scaly4 ,"s cry/all9e m9]als are made up ( t9y gra9s t are gr\p$ toge!r l ! gra9s 9 a lump ( sug>4 ,a m9]al occurr+ 9 ?is way is describ$ z granul>4 ,m descriptions ( cry/all9e m9]als are f\nd 9 ! section on ,texas rocks & m9]als 7pp4 #dc-ih74 ,illu/ration3 ,b>ite specim5 %[+ radial =m4 ,amorph\s ,m9]als ,an amorph\s m9]al1 unlike a cry/all9e m9]al1 does n h a def9ite1 ord]ly arrangem5t ( its atoms4 ,because ( ?is lack ( int]nal /ructure1 ! m9]al occurs 9 masses t h no regul> geometric %apes1 & x has no cry/al =m ( its own4 ,only a few m9]als are amorph\s4 ,,"s ,,di/+ui%+ ,,prop]ties ,,( ,,m9]als ,we use our s5ses ( sight1 he>+1 smell1 t\*1 & ta/e to become aw>e ( ! _w ar\nd u4 ,= example1 we recognize a fl[] by not+ its color1 its fragrance1 & ! texture1 %ape1 & arrangem5t ( its petals4 ,^! are "s ( its *>act]i/ic prop]ties4 ,a m9]al also has di/+ui%+ prop]ties1 among !m color1 lu/]1 & h>dness1 :i* help u id5tify x4 ,"s m9]als h a s+le out/&+ prop]ty1 su* z ! magnetism ( magnetite1 t makes !m easi] to recognize4 ,b to id5tify mo/ m9]als1 we ne$ to det]m9e n j "o1 b sev]al prop]ties4 ,illu/ration3 ,*alc$ony %[+ botryoidal =m4 ,color ,color is "o ( ! prop]ties we notice fir/4 ,! color ( "s m9]als is always ! same1 & x helps u to id5tify !m4 ,b x is n a dep5dable prop]ty to use 9 id5tify+ all m9]als1 because "s conta9 impurities t *ange or hide ! real color4 ,lu/] ,! lu/] is ! way ! surface ( a m9]al reflects light4 ,! lu/] ( a m9]al may be nonmetallic1 submetallic1 or metallic4 ,m9]al metals su* z gold1 silv]1 gal5a1 & pyrite h a metallic lu/]4 ,a few m9]als h a lu/] t is almo/1 b n q metallic--_! lu/] is submetallic4 ,a m9]al ) a nonmetallic lu/] may look vitre\s 7glassy71 silky1 res9\s 7l res971 greasy1 e>?y 7dull71 pe>ly1 or adamant9e 7brilliant74 ,transmission ( ,light ,"s m9]als all[ light to pass ?r\gh !m2 o!rs d n4 ,a m9]al is transp>5t if y c see bo? light & objects ?r\gh x1 z ?r\gh cle> glass4 ,if y c see only light1 b no objects1 z ?r\gh fro/$ glass1 ! m9]al is transluc5t4 ,:5 y hold an opaque m9]al up to ! light1 x looks d>k4 ,no light at all comes ?r\gh x1 ev5 ?r\gh ! ?9 edges4 ,illu/ration3 ,transp>5t m9]al4 ,h>dness ,"s m9]als are s(t & c be scrat*$ easily4 ,o!rs1 :i* are h>d]1 are resi/ant to scrat*+4 ,to measure a m9]al's h>dness1 we try to f9d out :i* sub/ances w scrat* x & :i* sub/ances w n scrat* x4 ,to d ?is 9 a g5]al way1 sev]al ord9>y objects--su* z a f+]nail1 a copp] p5ny1 a pocket knife1 a piece ( w9d[ glass1 & a /eel file--c be us$4 ,= a m exact way ( te/+ h>dness1 we c use t5 m9]als t make up :at is kn[n z ,mohs scale4 ,ea* m9]al 9 ?is scale has a diff]5t h>dness1 & ea* "o has be5 giv5 a numb] t repres5ts its h>dness4 ,= example1 talc1 ! s(te/ m9]al 9 ?is scale1 is giv5 a h>dness ( #a4 ,gypsum1 ! next s(te/ m9]al 9 ! scale1 has a h>dness ( #b4 ,diamond1 ! h>de/ m9]al kn[n1 is giv5 ! top h>dness ( #aj 9 ?is scale4 ,^! t5 m9]als are li/$ bel[4 ,alongside !m are five common objects ) _! h>dnesses4 #a--,talc #b--;,gypsum ,f+]nail--slightly ov] #b #c--;,calcite ,copp] p5ny--ab\t #c #d--;,fluorite #e--;,apatite ,pocket knife--slightly ov] #e #f--,or?oclase ,w9d[ glass--#e #g--,qu>tz ,/eel file--ab\t #f #h--,topaz #i--;,corundum #aj--;,diamond ,suppose1 = example1 t a m9]al c be scrat*$ by fluorite1 :i* has a h>dness ( #d on ,mohs scale1 b _c be scrat*$ by calcite1 :i* has a h>dness ( #c4 ,we !n "k t ?is m9]al is s(t] ?an fluorite1 b h>d] ?an calcite2 !re=e1 x has a h>dness ( ab\t #c4 ,9 ! same way1 if a m9]al c be scrat*$ by a pocket knife1 :i* is slightly m ?an #e 9 h>dness1 b n by a copp] p5ny1 :i* has a h>dness ( ab\t #c1 we "k !n t its h>dness is betwe5 #c & #e4 ,/reak or ,p[d] ,! /reak is ! m>k1 made ( f9e p[d]1 t a m9]al leaves z y rub x across a /reak plate4 ,a /reak plate is a flat piece ( :ite tile or porcela9 t has a dull1 unglaz$ surface4 ,! /reak plate is ab\t z h>d z qu>tz1 :i* is #g on ,mohs scale1 & y w n be able to use x = m9]als t h a great] h>dness4 ,= ^!1 y c obta9 ! p[d] by scrat*+ ! m9]al or by cru%+ a small piece ( x4 ,illu/ration3 ,a /reak plate is us$ to det]m9e ! color ( ! /reak or p[d] ( a m9]al4 ,! color ( ! /reak or p[d] is extremely helpful 9 id5tify+ "s m9]als4 ,= example1 hematite is a m9]al t may be any "o ( sev]al diff]5t colors1 b its /reak or p[d] is always r$di% br[n4 ,cleavage ,z !y break1 "s cry/all9e m9]als always split along a smoo?1 flat surface4 ,?is prop]ty is kn[n z cleavage4 ,"s cleavages are smoo? & p]fect2 o!rs are n s p]fect4 ,! cleavage surfaces1 because ( ! m9]al's cry/all9e int]nal /ructure1 are p>allel to possible cry/al faces1 ev5 ?\gh ! m9]al itself may occur z a cry/all9e mass )\t a p]fect cry/al %ape4 ,"s m9]als w cleave 9 only "o direction2 "s1 9 sev]al directions4 ,= example1 gal5a1 a m9]al f\nd 9 ,texas1 has p]fect cubic cleavage4 ,x cleaves 9 ?ree directions t are at "r angles to ea* o!r4 ,^! cleavage directions are p>allel to possible cubic cry/al faces1 & "s ( ! cleavage fragm5ts are cubes4 ,p>t+ ,a few m9]als sometimes %[ a k9d ( false cleavage kn[n z p>t+4 ,p>t+1 unlike cleavage1 is n con/ant & does n occur 9 e specim5 ( a p>ticul> m9]al4 ,= ?is reason1 x is n a v dep5dable means ( id5tification4 ,fracture ,m9]als also break 9 ano!r way4 ,:5 ! break is 9 a diff]5t direction f t ( ! cleavage or p>t+1 x is kn[n z ! fracture4 ,a fracture is call$ con*oidal if ! m9]al's brok5 surface is curv$ l ! inside ( a spoon or %ell4 ,?ick pieces ( glass break ) ?is con*oidal fracture4 ,a fracture is describ$ z hackly if ! brok5 surface has %>p1 jagg$ edges2 z ev51 if ! surface is g5]ally flat2 & z unev51 if x is r\gh & n flat4 ,if ! m9]al breaks into spl9t]s1 its fracture is call$ spl9t]y4 ,illu/ration3 ,con*oidal fracture4 ,specific ,gravity ,! specific gravity is a measure ( :e!r a m9]al is heavy or light4 ,x is a comp>ison ( ! weight ( a piece ( ! m9]al ) ! weight ( an equal volume ( wat]4 ,! m9]al qu>tz1 = example1 has a specific gravity ( #b4fe4 ,?is means t a piece ( qu>tz is a little m ?an #b times z heavy z an equal volume ( wat]4 ,accurate measurem5ts ( specific gravity c be made 9 a laboratory4 ,y c1 h[ev]1 le>n to e/imate specific gravities j by lift+ v>i\s m9]als & judg+ :e!r !y are heavy or light4 ,eff]vesc5ce 9 ,acid ,?is is a prop]ty t dep5ds on ! *emical composition ( ! m9]al4 ,c>bonate m9]als1 :i* conta9 79 addition to at lea/ "o o!r elem5t7 ?ree p>ts ( oxyg5 & "o "p ( c>bon1 c be te/$ ) dilute hydro*loric acid4 ,:5 a drop or two ( ?is acid is put on a c>bonate m9]al su* z calcite 7calcium c>bonate1 ,ca,c,o71 ! acid beg9s to bubble & fizz4 ,! fizz+ or eff]vesc5ce is caus$ by ! c>bon dioxide gas t is =m$ :5 ! acid & m9]al come 9 contact ) ea* o!r4 ,?is te/ is also helpful 9 id5tify+ rocks1 su* z lime/one & m>ble1 t conta9 c>bonate m9]als4 ,,"s ,,special ,,occurr5ces ,,( ,,m9]als ,cave ,deposits ,beautiful m9]al deposits occur 9 "s natural caves4 ,deposits t look l icicles1 call$ /alactites1 are f\nd hang+ f ! ceil+ ( a cave4 ,o!r deposits1 /alagmites1 are l ! /alactites except t !y jut upw>d f ! floor4 ,columns are =m$ f /alactites & /alagmites t h jo9$ toge!r4 ,9 addition1 "s caves conta9 %eet-l deposits t are spread along ! ceil+1 floor1 & walls4 ,^! deposits are call$ fl[/one4 ,calcite is "o ( ! m9]als t commonly =m cave deposits4 ,j a few ( ! caves 9 ,texas conta9 ^! deposits4 ,!y occur mo/ly 9 ! lime/one rocks t are s\? & s\?we/ ( ! ,llano uplift area ( c5tral ,texas4 ,"s ( ! comm]cial caves t conta9 good examples ( calcite deposits are locat$ ne> ,bo]ne 9 ,k5dall ,c\nty & ne> ,sonora 9 ,sutton ,c\nty4 ,calcite deposits also occur 9 ,longhorn ,cav]n1 a l>ge cave locat$ 9 ! ,longhorn ,cav]n ,/ate ,p>k ( ,burnet ,c\nty4 ,^! caves 7 =m$ by und]gr\nd wat]s t mov$ ?r\gh cracks & pores 9 ! lime/one rocks & dissolv$ passageways 9 !m4 ,aft] ! cave passages 7 made1 wat] conta9+ dissolv$ calcium c>bonate dripp$ into ! cave4 ,z x evaporat$1 ?is wat] left beh9d a deposit ( calcium c>bonate--! m9]al calcite4 ,y c bett] und]/& h[ ! cave deposits are =m$ by wat*+ icicles gr[ 9 wet1 freez+ wea!r4 ,fir/1 small hang+ drops ( wat] freeze1 & a small icicle =ms4 ,!n1 z m wat] drips ov] x & freezes1 ! icicle gr[s long] & wid]4 ,"s ( ! wat] drips completely ov] ! icicle & falls to ! gr\nd4 ,!re1 x ei!r freezes into a %eet ( ice1 or x beg9s to build upw>d to =m an upside-d[n icicle4 ,! wat] dripp+ d[n 9 ! caves evaporates in/ead ( freez+1 & 9 do+ s x leaves beh9d a deposit ( calcite4 ,illu/ration3 ,calcite /alactites & /alagmites 9 ! ,cav]ns ( ,sonora1 ,sutton ,c\nty1 ,texas4 ,photograph c\rtesy ( ! ,travel & ,in=mation ,division ( ! ,texas ,highway ,dep>tm5t4 ,concretions ,lime/one1 %ale1 & o!r s$im5t>y rocks commonly h scatt]$ ?r\gh\t !m masses ( o!r rocks & m9]als1 su* z limonite1 *]t1 & pyrite4 ,^! masses are call$ concretions4 ,concretions may be r\nd or oval1 or !y may h odd1 irregul> %apes4 ,!y--su* z "s ( ! limonite concretions ( ea/ ,texas--ev5 may look l g\rds or sweet potatoes4 ,concretions g5]ally are h>d] ?an ! surr\nd+ rocks4 ,"s are small] ?an peas1 b o!rs are sev]al feet wide4 7,! ^w nodule is us$ to describe small1 r\nd$ concretions z well z o!r small1 r\nd$ m9]al occurr5ces47 ,x is believ$ t "s concretions =m at ! same "t z ! rocks 9 :i* !y occur4 ,o!r concretions develop aft] ! rocks !mselves h =m$4 ,^! are deposit$ by und]gr\nd wat] t conta9s dissolv$ m9]al matt]4 ,! wat] seeps ?r\gh ! rocks & deposits m9]al matt] ar\nd an object 9 ! rock1 su* z a fossil or a gra9 ( s&1 to =m a concretion4 ,geodes ,geodes are r\nd$1 g5]ally holl[ masses t occur mo/ly 9 lime/ones4 ,!y are scatt]$ ?r\gh ! rocks & c be lift$ or dug out4 ,"s geodes are z small z walnuts1 & "s are z l>ge z basketballs4 ,mo/ ( !m h a r\gh1 dull-look+ out] surface4 ,if y break geodes op51 y w f9d t _m are l9$ ) beautiful cry/als ( calcite1 cele/ite1 or qu>tz t po9t inw>d t[>d ! holl[ c5t]4 ,illu/ration3 ,calcite geode f\nd 9 ,l[] ,cretace\s /rata ( we/]n ,travis ,c\nty1 ,texas4 ,x is ?\ght t a geode =ms :5 wat]1 c>ry+ dissolv$ m9]al mat]ial1 seeps into a cavity 9 ! rock1 !n deposits ! m9]al mat]ial z a l9+ 9 ! cavity4 ,?is l9+ becomes ! out] "p ( ! geode4 ,?us a geode--unlike a concretion1 :i* gr[s f ! c5t] outw>d--=ms f outside to inside4 ,"s ( ! ,l[] ,cretace\s lime/one rocks ( ,travis1 ,williamson1 & ,lampasas c\nties conta9 calcite & cele/ite geodes4 ,cele/ite geodes h also be5 f\nd 9 ,p]mian rocks 9 p>ts ( ,coke1 ,fi%]1 & ,nolan c\nties4 ,petrifi$ ,wood ,illu/ration3 ,petrifi$ wood f ,texas ,gulf ,coa/al ,pla94 ,we (t5 f9d "s m9]als occurr+ z petrifi$ wood4 7,petrifi$ wood includes silicifi$ wood1 opaliz$ wood1 agatiz$ wood1 & c>boniz$ wood47 ,petrifi$ wood =ms :5 plant mat]ial1 su* z a tree or a bu%1 is replac$ by a m9]al4 ,x is =m$ by und]gr\nd wat] c>ry+ dissolv$ m9]al matt]4 ,z ?is wat] seeps ?r\gh s$im5ts 9 :i* ! plants are buri$1 x gradually deposits agate1 *alc$ony1 calcite1 opal1 *alcocite1 or "s o!r m9]al 9 ! place ( ea* fib] ( ! wood4 ,by ?is sl[ *ange f plant to m9]al matt]1 ! orig9al %ape & /ructure ( ! wood rema9 un*ang$4 ,petrifi$ wood is commonly f\nd 9 "s ( ! ,t]ti>y1 ,p]mian1 & ,l[] ,cretace\s rocks ( ,texas4 7,see ,opal1 ,qu>tz1 ,copp] ,m9]als1 pp4 #gh1 #hd1 #eb74 ,,collect+ ,,rocks ,,& ,,m9]als ,p]haps y w\ld l to />t y\r own collection ( rocks & m9]als4 ,= ?is purpose y w ne$ a hamm] 7a prospector's hamm] ) a pick on "o end ( x is a good tool71 "s newspap]s to wrap ar\nd ! specim5s to keep !m f break+1 & a clo? bag 9 :i* to c>ry ! specim5s4 ,illu/ration3 ,prospector's hamm]4 ,be=e y />t to collect1 be sure to ask ! own]'s p]mission to g on 8 prop]ty4 ,if he agrees to let y come on 8 l&1 be c>eful ab\t clos+ gates1 & d n leave holes into :i* 8 live/ock might /ep & be injur$4 ,look out = snakes4 ,pl5ty ( rattl]s1 copp]heads1 & moccas9s are /ill left 9 ,texas4 ,&1 incid5tally1 collect+ is n all[$ 9 ,/ate or ,national p>ks4 ,to id5tify ! rocks & m9]als t y collect1 y probably w ne$ sev]al articles ) :i* to make simple te/s4 ,! foll[+ c be easily obta9$3 #a4 ,a pocket knife1 a copp] p5ny1 a piece ( w9d[ glass1 a /eel file1 & a piece ( qu>tz to te/ ! h>dness4 ,if y pref] to use a gr\p ( m9]als ( kn[n h>dness1 su* z ^? ( ,mohs scale describ$ on pages #af-ag1 y c ei!r collect y\r own or buy a prep>$ set f a m9]al supply h\se4 #b4 ,a /reak plate to te/ ! color ( ! m9]al's /reak4 ,m9]al /reak plates c be pur*as$1 or a piece ( unglaz$ tile c be us$4 #c4 ,a magnify+ glass to exam9e small cleavage surfaces1 cry/als1 & rock gra9s4 ,a numb] ( diff]5t k9ds c be b\ght1 f ! simple read+ glass to ! precisely made h& l5s4 ,a l5s ) t5-p[] magnification is good = g5]al use4 #d4 ,a small magnet to te/ :e!r or n a m9]al is magnetic4 #e4 ,dilute 7#aj7 hydro*loric acid 7,h,cl71 also kn[n z muriatic acid1 to te/ c>bonate rocks & m9]als4 ,y c buy a small bottle at a drug /ore4 ,be extremely c>eful 9 h&l+ ?is acid1 & keep x away f small *ildr5--x is a ,,poison4 ,if y spill any on y\rself1 x w burn y\r sk9 & eat holes 9 y\r clo!s4 ,illu/ration3 ,h& l5s4 ,! rock & m9]al id5tification *>ts on pages #bd-da w help y to make ! simple id5tification te/s 9 a me?odical way4 ,x is a good idea to h "s sy/em ( label+ y\r rock & m9]al specim5s4 ,"s collectors c>ry note pap] ) !m on field trips4 ,!n !y c write d[n ! location &1 if possible1 ! "n ( ! rock or m9]al4 ,?is in=mation is ei!r wrapp$ ) ! specim5 or /uck to x ) tape4 ,"o way to label l>ge collections is to put a small spot ( pa9t or f+]nail poli% on ea* ( ! rock & m9]al specim5s4 ,:5 ! pa9t has dri$1 a numb] c be writt5 on x 9 black ,india ink4 ,!n1 on a file c>d1 ! "n & ! numb] ( ! specim5 c be writt51 toge!r ) ! place :]e x 0 f\nd1 ! date ( collection1 & ! "n ( ! collector4 ,,rock ,,& ,,m9]al ,,id5tification ,,*>ts ,to help y id5tify !m1 v>i\s ,texas rocks & m9]als are li/$ toge!r 9 ! foll[+ *>ts accord+ to prop]ties t !y h 9 common4 ,al?\gh useful1 ! id5tification *>ts may n always give y p]fect results4 ,= example1 h>dness1 :i* is us$ z a guide1 is n to be completely reli$ ^u 9 ! id5tification ( rocks4 ,! *>ts on ! foll[+ pages p]ta9 only to ! rocks & m9]als t are describ$ 9 ?is book4 ,x is q possible t y w f9d rocks & m9]als 9 ,texas t are n includ$ 9 ^! *>ts4 ,if y f9d a rock or a m9]al t y are unable to id5tify1 y c *eck y\r local libr>y = ref]5ce books t may aid y 7sev]al su* ref]5ces are not$ on pages #ajj-aja74 ,if y ne$ fur!r help1 possibly ! sci5ce tea*] at a ne>by public s*ool w be able to id5tify ! specim5 = y4 ,or if a college or univ]sity is locat$ 9 y\r area 7especially "o t has a dep>tm5t ( geology71 y c obta9 help !re4 ,9 ,texas1 ! ,bureau ( ,economic ,geology is a m9]al in=mation c5t]4 ,mo/ o!r /ates h simil> geological rese>* & public-s]vice organizations4 ,o!r s\rces ( in=mation might be ! gem & m9]al societies t are f\nd 9 a numb] ( communities4 ,_m ( ! memb]s ( ^! organizations are exp]ts 9 ! id5tification ( rocks & m9]als4 ,h[ ,to ,use ! ,m9]al ,id5tification ,*>ts ,9 ! m9]al id5tification *>ts 7pp4 #bf-ch71 ! m9]als h be5 gr\p$1 fir/ ( all1 on ! basis ( lu/]3 ! fir/ gr\p includes ! m9]als t appe> metallic & almo/ metallic 7submetallic72 ! second gr\p includes ^? t appe> nonmetallic4 ,next1 ! m9]als h be5 arrang$ )9 ! two gr\ps accord+ to color4 ,aft] y h det]m9$ ! lu/] & ! color ( an unkn[n m9]al1 turn to ! ,key to ,m9]al ,id5tification ,*>ts on page #be4 ,x w direct y to ! prop] m9]al *>t4 ,m9]al ,*>ts #a ?r\gh #e1 :i* include ! m9]als ( v>i\s colors ) metallic & submetallic lu/]s1 are subdivid$ accord+ to ! h>dness ( ! m9]als4 ,to det]m9e ! h>dness ( a m9]al t has "o ( ^! lu/]s1 y c make ! foll[+ te/s3 #a4 ,w ! m9]al readily leave a m>k on pap]8 #b4 ,if x w n readily leave a m>k on pap]1 w an ord9>y pocket knife scrat* x8 #c4 ,is x too h>d to be scrat*$ by an ord9>y pocket knife8 ,m9]al ,*>ts #f ?r\gh #ae are = ! nonmetallic m9]als ( v>i\s colors4 ,!y1 too1 are subdivid$ accord+ to ! h>dness ( ! m9]als1 z foll[s3 #a4 ,c ! m9]al be scrat*$ by a f+]nail8 #b4 ,if x _c be scrat*$ by a f+]nail1 c x be scrat*$ by a copp] p5ny8 #c4 ,if x _c be scrat*$ by a copp] p5ny1 c x be scrat*$ by an ord9>y pocket knife8 #d4 ,if x _c be scrat*$ by an ord9>y pocket knife1 c x be scrat*$ by a piece ( qu>tz8 #e4 ,is x too h>d to be scrat*$ by qu>tz8 ,:5 ! lu/]1 color1 & h>dness ( a m9]al h be5 det]m9$1 y may f9d t sev]al m9]als on ! *>ts fit ! description4 ,to n>r[ y\r *oice1 y c !n te/ o!r prop]ties ( ! m9]al4 ,notice ! 8rem>ks0 column on ! *>ts4 ,9 x1 is m5tion$ any?+ t is di/9ctive ab\t ! m9]al4 ,= m complete m9]al id5tification li/s & tables1 y c use textbooks1 su* z ,dana's ,manual ( ,m9]alogy1 revis$ by ,c4 ,s4 ,hurlbut1 ,jr41 or ,m9]alogy1 by ,e4 ,h4 ,kraus1 ,w4 ,f4 ,hunt1 & ,l4 ,s4 ,ramsdell4 ,key to ,m9]al ,id5tification ,*>ts ,if ! m9]al has a metallic or submetallic lu/]1 & is3 ,consult ,m9]al ,*>t :ite #a gray #b yell[ #c br[n #d black #e ,if ! m9]al has a nonmetallic lu/]1 & is3 ,consult ,m9]al ,*>t :ite #f gray #g yell[ #h br[n #i black #aj gre5 #aa blue #ab r$ or p9k #ac purple or #ad violet colorless #ae ,m9]al ,id5tification ,*>ts ,*>t ,m9]al ,/reak ,rem>ks ,h>dness ,no4 #a4 ,,metallic lu/]1 ,,:ite color ,a4 ,does n readily leave m>k on pap] b c be scrat*$ by ord9>y pocket knife ,native silv] ,%9y silv] ,silv]-:ite #b-c :ite1 unless color t t>ni%$ t>ni%es to gray1 black1 or yell[i% br[n2 heavy2 c be flatt5$ :5 hit ) hamm] #b4 ,,metallic or ,,submetallic lu/]1 ,,gray color ,a4 ,w leave m>k on pap] ,arg5tite ,%9y1 blacki% ,lead-gray color #b-b to lead gray t t>ni%es to dull black2 knife cuts x smoo?ly2 heavy2 may occur z masses & coat+s ,gal5a ,grayi% black ,%9y lead-gray #b color2 heavy2 cube-%ap$ fragm5ts & cry/als ,graphite ,black ,/eel-gray color2 #a-b greasy feel2 v s(t2 splits into ?9 flakes ,b4 ,does n readily leave m>k on pap] b c be scrat*$ by ord9>y pocket knife ,*alcocite ,grayi% black ,%9y lead-gray #b-c color t t>ni%es to dull black2 knife cuts x smoo?ly2 may h black sooty coat+2 commonly occurs z compact or granul> masses ,holl&ite ,black ,silv]y-gray #d-f color2 may occur z r\nd$ masses ,c4 ,_c be scrat*$ by ord9>y pocket knife ,braunite ,/eel gray or ,d>k /eel-gray #f-f black color & submetallic lu/] ,hematite ,d>k r$di% br[n ,/eel-gray color2 #e-f commonly occurs 7may be z granul> or s(t]7 compact masses2 %9y1 scaly v>iety is specul> hematite2 notice /reak ,holl&ite ,black ,silv]y-gray #d-f color2 may occur z r\nd$ masses #c4 ,,metallic lu/]1 ,,yell[ color ,a4 ,does n readily leave m>k on pap] b c be scrat*$ by ord9>y pocket knife ,*alcopyrite ,gre5i% black ,brass-yell[ or #c-d gold5-yell[ color t may t>ni% & %[ ra9b[-l colors2 commonly massive2 notice /reak ,gold ,%9y gold5 ,%9y yell[ #b-c yell[ color2 extremely heavy2 flatt5s :5 hit ) hamm]2 notice /reak ,b4 ,_c be scrat*$ by ord9>y pocket knife ,pyrite ,black1 gre5i% ,%9y1 pale #f-f black1 or gold5-yell[ or br[ni% black brass-yell[ color t may t>ni%2 occurs z gra9s1 z masses1 or z cubes or o!r cry/al %apes2 notice h>dness & /reak #d4 ,,metallic or ,,submetallic lu/]1 ,,br[n color ,a4 ,does n readily leave m>k on pap] b c be scrat*$ by ord9>y pocket knife ,limonite ,ru/y yell[i% ,d>k-br[n color2 #e-e br[n "s specim5s h a %9y black surface2 notice /reak ,b4 ,_c be scrat*$ by an ord9>y pocket knife ,cassit]ite ,pale br[n1 pale ,br[n2 #f-g yell[ or :ite submetallic2 heavy2 notice /reak ,hematite ,d>k r$di% br[n ,d>k br[n color2 #e-f commonly occurs 7may be z granul> or s(t]7 compact masses2 notice /reak ,limonite ,ru/y1 yell[i% ,d>k br[n color2 #e-e br[n "s specim5s h a %9y black surface2 notice /reak #e4 ,,metallic or ,,submetallic lu/]1 ,,black color ,a4 ,w leave m>k on pap] ,arg5tite ,%9y1 blacki% ,lead-gray color #b-b to lead grey t t>ni%es to dull black2 knife cuts x smoo?ly2 heavy2 may occur z masses & coat+s ,graphite ,black ,greasy feel2 v #a-b s(t2 splits into ?9 flakes ,pyrolusite ,black ,v s(t2 w #a-b soil f+]s2 may be p[d]y ,b4 ,does n readily leave m>k on pap] b c be scrat*$ by an ord9>y pocket knife ,*alcocite ,grayi% black ,%9y lead-gray #b-c color t t>ni%es to dull black2 knife cuts x smoo?ly2 may h a black sooty coat+2 commonly occurs z compact or granul> masses ,holl&ite ,black ,may occur z #d-f r\nd$ masses ,limonite ,ru/y1 yell[i% ,"s specim5s #e-e br[n h %9y black surface2 notice /reak ,c4 ,_c be scrat*$ by an ord9>y pocket knife ,braunite ,/eel gray or ,lu/] is #f-f black submetallic ,cassit]ite ,pale br[n1 pale ,submetallic #f-g yell[1 or :ite lu/]2 heavy2 notice /reak ,hematite ,d>k r$di% br[n ,notice /reak2 #e-f commonly occurs 7may be z granul> or s(t]7 compact masses ,holl&ite ,black ,may occur z #d-f r\nd$ masses ,limonite ,ru/y yell[i% ,"s specim5s #e-e br[n h %9y black surface2 notice /reak ,magnetite ,black ,fragm5ts cl+ #f to a magnet ,pit*bl5de ,br[ni% black ,br[ni% black1 #e gre5i% black1 or black2 radioactive2 heavy2 may appe> dull or greasy #f4 ,,nonmetallic lu/]1 ,,:ite color ,a4 ,c be scrat*$ by a f+]nail ,c]>gyrite ,%9y :ite or ,appe>s waxy2 #a-a gray knife cuts x smoo?ly2 turns violet br[n to black :5 expos$ to light ,gypsum ,:ite ,s(t2 occurs z #b cry/als or z fibr\s1 granul>1 compact1 or e>?y masses ,talc ,:ite ,knife cuts x #a smoo?ly2 feels soapy or greasy2 splits into ?9 flakes ,b4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,anhydrite ,:ite ,commonly occurs #c-c z sug>y-look+ masses ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,calcite ,:ite ,dilute #c hydro*loric acid fizzes on calcite2 p]fect cleavage 9 #c directions gives rhomb-%ap$ fragm5ts ,cele/ite ,:ite ,n q z #c-c heavy z b>ite2 cry/als commonly prism-%ap$ or flat-look+2 "s cleavage fragm5ts are flat & slab-l ,halite ,:ite ,salty ta/e2 #b dissolves 9 wat]2 cube-%ap$ cleavage fragm5ts ,c4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,anhydrite ,:ite ,commonly occurs #c-c z sug>y-look+ masses ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,cele/ite ,:ite ,n q z #c-c heavy z b>ite2 cry/als commonly prism-%ap$ or flat-look+2 "s cleavage fragm5ts are flat & slab-l ,dolomite ,:ite ,commonly occurs #c-d z granul> masses & z rhomb-%ap$ cry/als2 dilute hydro*loric acid may fizz slightly on dolomite ,fluorite ,:ite ,cleavage 9 #d #d directions c give fragm5ts t are %ap$ l octah$rons2 cry/als commonly cubes ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull2 milky :ite & blui%-:ite preci\s opal %[s plays ( colors ,d4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,feldsp> ,:ite ,glassy or pe>ly #f lu/]2 good cleavage 9 #b directions t meet at an angle ( #ij or ne> #ij2 common 9 granite & pegmatite rocks ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull2 milky :ite & blui%-:ite preci\s opal %[s plays ( colors ,qu>tz ,:ite ,curv$ con*oidal #g fracture2 occurs z milky qu>tz1 *]t1 & *alc$ony2 cry/als commonly #f-sid$ prisms ) pyramid-l ends #g4 ,,nonmetallic lu/]1 ,,gray color ,a4 ,c be scrat*$ by a f+]nail ,amphibole asbe/os ,:ite ,made up ( #a-b sl5d]1 flexible fib]s t c be pull$ ap>t ,c]>gyrite ,%9y :ite or ,appe>s waxy2 #a-a gray knife cuts x smoo?ly2 turns violet br[n to black :5 expos$ to light ,gypsum ,:ite ,s(t2 occurs z #b cry/als or z fibr\s1 granul>1 compact1 or e>?y masses ,sulfur ,:ite or pale ,w burn ) a #a-b yell[ blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,talc ,:ite ,knife cuts x #a smoo?ly2 feels soapy or greasy2 splits into ?9 flakes ,b4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,amphibole asbe/os ,:ite ,made up ( #a-b sl5d]1 flexible fib]s t c be pull$ ap>t ,anhydrite ,:ite ,commonly occurs #c-c z sug>y-look+ masses ,calcite ,:ite ,dilute #c hydro*loric acid fizzes on calcite2 p]fect cleavage 9 #c directions gives rhomb-%ap$ fragm5ts ,cele/ite ,:ite ,cry/als commonly #c-c prism-%ap$ or flat-look+2 "s cleavage fragm5ts are flat & slab-l ,halite ,:ite ,salty ta/e2 #b dissolves 9 wat]2 cube-%ap$ cleavage fragm5ts ,sulfur ,:ite or pale ,w burn ) a #a-b yell[ blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,c4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,anhydrite ,:ite ,commonly occurs #c-c z sug>y-look+ masses ,cele/ite ,:ite ,cry/als commonly #c-c prism-%ap$ or flat-look+2 "s cleavage fragm5ts are flat & slab-l ,dolomite ,:ite ,commonly occurs #c-d z granul> masses & z rhomb-%ap$ cry/als2 dilute hydro*loric acid may fizz slightly on dolomite ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull ,d4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,feldsp> ,:ite ,glassy or pe>ly #f lu/]2 good cleavage 9 #b directions t meet at an angle ( #ij or ne> #ij2 common 9 granite & pegmatite rocks ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull ,qu>tz ,:ite ,curv$ con*oidal #g fracture2 occurs z *]t & *alc$ony #h4 ,,nonmetallic lu/]1 ,,yell[ color ,a4 ,c be scrat*$ by a f+]nail ,c>notite ,yell[ ,bright can>y #b yell[ or lemon yell[2 radioactive2 occurs z cru/s & p[d]y masses ,gypsum ,:ite ,yell[i%2 s(t2 #b occurs z cry/als or z fibr\s1 granul>1 compact or e>?y masses ,limonite ,ru/y yell[i% ,br[ni%-yell[ #a br[n color2 may be s(t & e>?y ,muscovite 7:ite ,:ite ,light color$2 #b-b mica7 splits into ?91 flat1 transp>5t %eets t w b5d )\t break+ ,sulfur ,:ite or pale ,w burn ) a #a-b yell[ blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,uranophane ,light yell[ to ,yell[ to #b-c light yell[ yell[-orange orange color2 radioactive ,b4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,calcite ,:ite ,yell[i%2 dilute #c hydro*loric acid fizzes on calcite2 p]fect cleavage 9 #c directions gives rhomb-%ap$ fragm5ts ,muscovite 7:ite ,:ite ,light color$2 #b-b mica7 splits into ?91 flat1 transp>5t %eets t w b5d )\t break+ ,sulfur ,:ite or pale ,w burn ) a #a-b yell[ blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,uranophane ,light yell[ to ,yell[ to #b-c light yell[ yell[-orange orange color2 radioactive ,c4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull ,d4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,feldsp> ,:ite ,glassy or pe>ly #f lu/]2 good cleavage 9 #b directions t meet at an angle ( #ij or ne> #ij ,g>net ,:ite ,commonly occurs #f-g z cry/als ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull ,qu>tz ,:ite ,curv$ con*oidal #g fracture2 br[ni%-yell[ smoky qu>tz cry/als commonly #f-sid$ prisms ) pyramid-l ends2 *alc$ony & jasp] may be a %ade ( yell[1 too #i4 ,,nonmetallic lu/]1 ,,br[n color ,a4 ,c be scrat*$ by a f+]nail ,gypsum ,:ite ,br[ni%2 s(t2 #b occurs z cry/als or z fibr\s1 granul>1 compact or e>?y masses ,limonite ,ru/y yell[i% ,may be s(t & #a br[n e>?y ,muscovite 7:ite ,:ite ,light color$2 #b-b mica7 splits into ?91 flat1 transp>5t %eets t w b5d )\t break+ ,sulfur ,:ite or pale ,w burn ) a #a-b yell[ blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,b4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,biotite 7black mica7 ,:ite ,d>k br[n2 #b-c splits into ?91 flat %eets t w b5d )\t break+ ,calcite ,:ite ,dilute #c hydro*loric acid fizzes on calcite2 p]fect cleavage 9 #c directions gives rhomb-%ap$ fragm5ts ,halite ,:ite ,salty ta/e2 #b dissolves 9 wat]2 cube-%ap$ cleavage fragm5ts ,muscovite 7:ite ,:ite ,light color$2 #b-b mica7 splits into ?91 flat1 transp>5t %eets t w b5d )\t break+ ,sulfur ,:ite or pale ,w burn ) a #a-b yell[ blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,c4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,dolomite ,:ite ,commonly occurs #c-d z granul> masses & z rhomb-%ap$ cry/als2 dilute hydro*loric acid may fizz slightly on dolomite ,fluorite ,:ite ,cleavage 9 #d #d directions c give fragm5ts t are %ap$ l octah$rons2 cry/als commonly cube-%ap$ ,d4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,cassit]ite ,pale br[n1 pale ,br[n1 r$di% #f-g yell[1 or :ite br[n1 or yell[i% br[n2 heavy2 dull to brilliant lu/] ,feldsp> ,:ite ,glassy or pe>ly #f lu/]2 good cleavage 9 #b directions t meet at an angle ( #ij or ne> #ij2 common 9 granite & pegmatite rocks ,g>net ,:ite ,commonly occurs #f-g z cry/als ,qu>tz ,:ite ,curv$ con*oidal #g fracture2 br[n smoky qu>tz cry/als commonly #f-sid$ prisms ) pyramid-l ends2 *alc$ony1 *]t1 & jasp] may be a %ade br[n1 too ,t\rmal9e ,:ite ,d>k br[n #g-g v>iety is dravite2 notice h>dness1 /riations on cry/als1 & triangul> cross section ( "s cry/als ,e4 ,_c be scrat*$ by qu>tz ,t\rmal9e ,:ite ,d>k br[n #g-g v>iety is dravite2 notice h>dness1 /riations on cry/als1 & triangul> cross section ( "s cry/als #aj4 ,,nonmetallic lu/]1 ,,black color ,a4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,biotite 7black mica7 ,:ite ,splits into ?91 #b-c flat %eets t w b5d )\t break+ ,b4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,g>net ,:ite ,commonly occurs #f-g z cry/als ,qu>tz ,:ite ,curv$ con*oidal #g fracture2 br[ni%-black smoky qu>tz cry/als commonly #f-sid$ prisms ) pyramid-l ends2 *alc$ony & *]t may be black1 too ,t\rmal9e ,:ite ,black v>iety is #g-g s*orl2 notice h>dness1 /riations on cry/als1 & triangul> cross section ( "s cry/als ,c4 ,_c be scrat*$ by qu>tz ,t\rmal9e ,:ite ,black v>iety is #g-g s*orl2 notice h>dness1 /riations on cry/als1 & triangul> cross section ( "s cry/als #aa4 ,,nonmetallic lu/]1 ,,gre5 color ,a4 ,c be scrat*$ by a f+]nail ,amphibole asbe/os ,:ite ,made up ( #a-b sl5d]1 flexible fib]s t c be pull$ ap>t ,c]>gyrite ,%9y :ite or ,light gre5i% #a-a gray color2 appe>s waxy2 knife cuts x smoo?ly2 turns violet br[n to black :5 expos$ to light ,muscovite 7:ite ,:ite ,light color$2 #b-b mica7 splits into ?91 flat1 transp>5t %eets t w b5d )\t break+ ,sulfur ,:ite or pale ,gre5i%2 w #a-b yell[ burn ) a blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,talc ,:ite ,light gre5i% #a color2 knife cuts x smoo?ly2 feels soapy or greasy2 splits into ?9 flakes ,b4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,amphibole asbe/os ,:ite ,made up ( #a-b sl5d]1 flexible fib]s t c be pull$ ap>t ,biotite 7black mica7 ,:ite ,d>k gre52 #b-c splits into ?91 flat1 transluc5t %eets t w b5d )\t break+ ,calcite ,:ite ,dilute #c hydro*loric acid fizzes on calcite2 p]fect cleavage 9 #c directions gives rhomb-%ap$ fragm5ts ,halite ,:ite ,gre5i% t9t2 #b salty ta/e2 dissolves 9 wat]2 cube-%ap$ cleavage fragm5ts ,muscovite 7:ite ,:ite ,light color$2 #b-b mica7 splits into ?91 flat1 transp>5t %eets t w b5d )\t break+ ,s]p5t9e ,:ite ,two k9ds3 silky #b-d & fibr\s1 waxy & platy ,sulfur ,:ite or pale ,gre5i%2 w #a-b yell[ burn ) a blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,c4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,fluorite ,:ite ,cleavage 9 #d #d directions c give fragm5ts %ap$ l octah$rons2 cry/als commonly cubes ,mala*ite ,gre5 ,bright gre5 #c-d color2 dilute hydro*loric acid w fizz on mala*ite ,s]p5t9e ,:ite ,two k9ds3 silky #b-d & fibr\s1 waxy & platy ,d4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,feldsp> ,:ite ,glassy or pe>ly #f lu/]2 good cleavage 9 #b directions t meet at an angle ( #ij or ne> #ij ,g>net ,:ite ,commonly occurs #f-g z cry/als #ab4 ,,nonmetallic lu/]1 ,,blue color ,a4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,anhydrite ,:ite ,commonly occurs #c-c z sug>y-look+ masses ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,calcite ,:ite ,dilute #c hydro*loric acid fizzes on calcite2 p]fect cleavage 9 #c directions gives rhomb-%ap$ fragm5ts ,cele/ite ,:ite ,n q z #c-c heavy z b>ite2 cry/als commonly prism-%ap$ or flat-look+2 "s cleavage fragm5ts are flat & slab-l ,halite ,:ite ,salty ta/e2 #b dissolves 9 wat]2 cube-%ap$ cleavage fragm5ts ,b4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,anhydrite ,:ite ,commonly occurs #c-c z sug>y-look+ masses ,azurite ,blue ,bright1 int5se #c-d blue color2 dilute hydro*loric acid w fizz on azurite ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,cele/ite ,:ite ,n q z #c-c heavy z b>ite2 cry/als commonly prism-%ap$ or flat-look+2 "s cleavage fragm5ts are flat & slab-l ,fluorite ,:ite ,cleavage 9 #d #d directions c give fragm5ts t are %ap$ l octah$rons2 cry/als commonly cube-%ap$ ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull2 milky :ite & blui%-:ite preci\s opal %[s plays ( colors ,c4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,feldsp> ,:ite ,glassy or pe>ly #f lu/]2 good cleavage 9 #b directions t meet at an angle ( #ij or ne> #ij ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull2 milky :ite & blui%-:ite preci\s opal %[s plays ( colors ,qu>tz ,:ite ,curv$ con*oidal #g fracture2 occurs z cry/all9e qu>tz & z blui% *alc$ony ,d4 ,_c be scrat*$ by qu>tz ,topaz ,:ite ,p]fect basal #h cleavage gives flat1 plate-l fragm5ts2 notice h>dness #ac4 ,,nonmetallic lu/]1 ,,r$ or ,,p9k color ,a4 ,c be scrat*$ by a f+]nail ,gypsum ,:ite ,r$di%2 s(t2 #b occurs z cry/als or z fibr\s1 granul>1 compact1 or e>?y masses ,hematite ,d>k r$di% br[n ,br[ni%-r$ #a color2 s(t & e>?y ,sulfur ,:ite or pale ,r$di%2 w #a-b yell[ burn ) blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,b4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,anhydrite ,:ite ,p9ki% t9t2 #c-c commonly occurs z sug>y-look+ masses ,b>ite ,:ite ,p9ki% t9t2 #c-c r heavy2 cleavage fragm5ts may be flat & slab-l ,calcite ,:ite ,p9k color2 #c dilute hydro*loric acid fizzes on calcite2 p]fect cleavage 9 #c directions gives rhomb-%ap$ fragm5ts ,c9nab> ,d>k r$ ,d>k r$ or #b bright yell[i%-r$ color2 %9y1 brilliant lu/] :5 pure2 dull & e>?y :5 impure2 heavy ,halite ,:ite ,r$di% t9t2 #b salty ta/e2 dissolves 9 wat]2 cube-%ap$ cleavage fragm5ts ,sulfur ,:ite or pale ,r$di%2 w #a-b yell[ burn ) blue flame2 commonly f\nd z cry/als1 cru/s1 or gra9s ,c4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,anhydrite ,:ite ,p9ki% t9t2 #c-c commonly occurs z sug>y-look+ masses ,b>ite ,:ite ,p9ki% t9t2 #c-c r heavy2 cleavage fragm5ts may look flat & slab-l ,dolomite ,:ite ,p9k color2 #c-d commonly occurs z granul> masses & z rhomb-%ap$ cry/als2 dilute hydro*loric acid may fizz slightly on dolomite ,fluorite ,:ite ,p9k color2 #d cleavage 9 #d directions c give fragm5ts t are %ap$ l octah$rons2 cry/als commonly cubes ,opal ,:ite ,r$di% color2 #e-f curv$1 con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull ,d4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,feldsp> ,:ite ,glassy or pe>ly #f lu/]2 good cleavage 9 #b directions t meet at an angle ( #ij or ne> #ij ,g>net ,:ite ,commonly occurs #f-g z cry/als ,opal ,:ite ,r$di% color2 #e-f curv$1 con*oidal fracture2 may appe> glassy1 greasy1 res9\s1 or dull ,qu>tz ,:ite ,curv$1 #g con*oidal fracture2 occurs z rose qu>tz1 z p9k *]t1 & z agate & jasp] #ad4 ,,nonmetallic lu/]1 ,,purple or ,,violet color ,a4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,fluorite ,:ite ,cleavage 9 #d #d directions c give fragm5ts t are %ap$ l octah$rons2 cry/als commonly cubes ,b4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,qu>tz1 v>iety3 ,:ite ,curv$1 #g ame?y/ con*oidal fracture2 ame?y/ cry/als commonly #f-sid$ prisms ) pyramid-l ends #ae4 ,,nonmetallic lu/]1 ,,colorless ,a4 ,c be scrat*$ by a f+]nail ,c]>gyrite ,%9y :ite or ,appe>s waxy2 #a-a gray knife cuts x smoo?ly2 turns violet br[n to black :5 expos$ to light ,gypsum ,:ite ,transp>5t #b sel5ite v>iety commonly occurs z flat1 diamond-%ap$ cry/als2 splits into ?91 flat %eets t w n b5d )\t break+ ,muscovite 7:ite ,:ite ,splits into ?91 #b-b mica7 flat1 transp>5t %eets t w b5d )\t break+ ,b4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by a copp] p5ny ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,calcite ,:ite ,dilute #c hydro*loric acid fizzes on calcite2 p]fect cleavage 9 #c directions gives rhomb-%ap$ fragm5ts ,cele/ite ,:ite ,n q z #c-c heavy z b>ite2 cry/als commonly prism-%ap$ or flat-look+2 "s cleavage fragm5ts are flat & slab-l ,halite ,:ite ,salty ta/e2 #b dissolves 9 wat]2 cube-%ap$ cleavage fragm5ts ,muscovite 7:ite ,:ite ,splits into ?91 #b-b mica7 flat1 transp>5t %eets t w b5d )\t break+ ,c4 ,_c be scrat*$ by a copp] p5ny b c be scrat*$ by an ord9>y pocket knife ,b>ite ,:ite ,r heavy2 #c-c cleavage fragm5ts may be flat & slab-l ,cele/ite ,:ite ,n q z #c-c heavy z b>ite2 cry/als commonly prism-%ap$ or flat-look+2 "s cleavage fragm5ts are flat & slab-l ,dolomite ,:ite ,commonly occurs #c-d z granul> masses & z rhomb-%ap$ cry/als2 dilute hydro*loric acid may fizz slightly on dolomite ,fluorite ,:ite ,cleavage 9 #d #d directions c give fragm5ts t are %ap$ l octah$rons2 cry/als commonly cubes ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 transp>5t hyalite v>iety resembles ice ,d4 ,_c be scrat*$ by an ord9>y pocket knife b c be scrat*$ by qu>tz ,opal ,:ite ,curv$1 #e-f con*oidal fracture2 transp>5t hyalite v>iety resembles ice ,qu>tz ,:ite ,curv$1 #g con*oidal fracture2 rock cry/al qu>tz commonly #f-sid$ prism ) pyramid-l ends ,e4 ,_c be scrat*$ by qu>tz ,topaz ,:ite ,p]fect basal #h cleavage gives flat1 plate-l fragm5ts2 notice h>dness ,h[ ,to ,use ! ,rock ,id5tification ,*>ts ,9 ! rock id5tification *>ts on pages #dj-da1 ! ,texas rocks describ$ 9 ?is book are arrang$ 9 f\r major gr\ps accord+ to _! texture4 #a4 ,glassy 7! rocks are smoo?1 d>k1 & %9y7 #b4 ,compact1 dull1 or /ony 7! rocks are smoo? & dull1 b ! individual gra9s are too small to be recogniz$7 #c4 ,granul> 7at lea/ "s ( ! individual gra9s ( ! rocks are l>ge en\gh to be se5 )\t a magnify+ glass7 #d4 ,fragm5tal 7! rocks are made up ( fragm5ts t are ei!r loose or cem5t$ toge!r7 ,consult ,rock ,*>t #a1 if ! rock is glassy2 ,*>t #b1 if x is compact1 dull1 or /ony2 ,*>t #c1 if x is granul>2 & ,*>t #d1 if x is fragm5tal4 ,two ( ! rock *>ts are subdivid$4 ,9 ,rock ,*>t #b1 ! compact1 dull1 or /ony rocks are arrang$ accord+ to h>dness z foll[s3 ,a4 ,rocks t c be scrat*$ by a f+]nail ,b4 ,rocks t _c be scrat*$ by a f+]nail b c be scrat*$ by an ord9>y pocket knife ,c4 ,rocks t _c be scrat*$ by an ord9>y pocket knife ,9 ,rock ,*>t #c1 ! granul> rocks also are arrang$ accord+ to h>dness into3 ,a4 ,rocks t c be scrat*$ by an ord9>y pocket knife ,b4 ,rocks t _c be scrat*$ by an ord9>y pocket knife ,^! h>d] rocks are subdivid$ into ?ree gr\ps3 #a4 ,^? t h gra9s ( ab\t equal size #b4 ,^? ) l>ge easily se5 gra9s t are scatt]$ ?r\gh a mass ( f9] gra9s #c4 ,^? rocks ^: gra9s are arrang$ 9 lay]s ,9 ! 8rem>ks0 column ( ! rock id5tification *>ts are includ$ fur!r te/s t w aid y 9 id5tify+ ! rock4 ,= a m complete rock det]m9ation *>t1 y c consult a textbook1 su* z ,rocks & ,rock ,m9]als1 by ,l4 ,v4 ,pirsson & ,a4 ,knopf4 ,rock ,id5tification ,*>ts ,*>t ,rock ,rem>ks ,no4 #a4 ,,glassy appe>ance 7rock is d>k1 smoo?1 & %9y7 ,obsidian ,entire rock is glassy ,vitrophyre ,cry/all9e gra9s are scatt]$ ?r\gh ! d>k glassy mass #b4 ,,compact1 ,,dull1 ,,or ,,/ony appe>ance 7individual gra9s too small to be recogniz$7 ,a4 ,c be scrat*$ by a f+]nail ,*alk ,dilute hydro*loric acid fizzes on x ,clay ,e>?y odor :5 brea!d on ,diatomite ,crumbly ,rock gypsum ,made up ( ! m9]al gypsum ,soap/one ,soapy or greasy feel ,b4 ,_c be scrat*$ by a f+]nail b c be scrat*$ by ord9>y pocket knife ,dolomite ,dilute hydro*loric acid may fizz slightly on x2 w fizz if rock is p[d]$ ,lime/one ,dilute hydro*loric acid fizzes on x ,s]p5t9e rock ,commonly "s %ade ( gre5 ,%ale ,breaks 9 flat1 ?9 flakes2 e>?y odor ,c4 ,_c be scrat*$ by an ord9>y pocket knife ,basalt ,d>k color$ & heavy ,*]t ,h>d1 smoo?1 & porcela9-l ,rhyolite ,light to d>k color$2 may %[ /reaks or fl[ /ructure #c4 ,,granul> appe>ance 7at lea/ "s ( ! individual gra9s are l>ge en\gh to be se5 )\t a magnify+ glass7 ,a4 ,c be scrat*$ by an ord9>y pocket knife ,lime/one ,dilute hydro*loric acid w fizz on x ,m>ble ,dilute hydro*loric acid w fizz on calcite m>ble1 & x may fizz slightly on dolomite m>ble ,rock gypsum ,made up ( ! m9]al gypsum ,rock salt ,has a salty ta/e2 made up ( ! m9]al halite ,b4 ,g5]ally _c be scrat*$ by an ord9>y pocket knife 7"s s*i/ is s(t]7 ,gra9s are ( ab\t equal size 7equigranul>7 #a4 ,granite ,qu>tz & feldsp> gra9s int]lock ,pegmatite ,l>ge int]lock+ gra9s2 commonly feldsp>1 qu>tz1 mica ,qu>tzite ,rock breaks across ! qu>tz gra9s ,s&/one ,rock breaks ?r\gh ! cem5t b ar\nd ! s& gra9s ,easily se5 gra9s are scatt]$ ?r\gh a mass ( f9] gra9s #b4 ,basalt ,d>k color$1 heavy rock ,llanite ,ru/y p9k feldsp> & blue qu>tz gra9s emb$d$ 9 a br[ni% rock mass ,rhyolite porphyry ,light to d>k color$ rock2 may %[ /reaks or fl[ /ructure ,gra9s are arrang$ 9 lay]s #c4 ,gneiss ,int]lock+ gra9s are 9 /raight or wavy b&s ,s*i/ ,splits 9 ?9 lay]s2 "s s*i/ is s(t en\gh to be scrat*$ by a knife #d4 ,,fragm5tal appe>ance 7rocks are made up ( fragm5ts t are ei!r loose or cem5t$ toge!r7 ,breccia ,angul>1 gravel-size fragm5ts t are cem5t$ toge!r ,conglom]ate ,r\nd$1 gravel-size fragm5ts t are cem5t$ toge!r ,coqu9a ,%ells & %ell fragm5ts t are cem5t$ toge!r ,gravel ,loose fragm5ts ,pulv]ul5t ,loose1 p[d]y fragm5ts2 dilute lime/one hydro*loric acid fizzes on !m ,s& ,loose fragm5ts no l>g] ?an a p9head ,s&/one ,s& fragm5ts t are cem5t$ toge!r ,volcanic a% ,loose1 f9e1 gritty p>ticles ,illu/ration3 ,physiographic outl9e map ( ,texas4 ,,descriptions ,,( ,,"s ,,texas ,,rocks ,,& ,,m9]als ,! pages t foll[ conta9 descriptions ( ,texas rocks & m9]als4 ,! descriptions are giv5 9 alphabetical ord]1 except t relat$ v>ieties are describ$ toge!r4 ,= example1 agate1 ame?y/1 *]t1 fl9t1 jasp]1 onyx1 & *alc$ony are discuss$ "u qu>tz1 because !y are v>ieties ( qu>tz4 ,! descriptions include ! prop]ties ( ! rock or m9]al t w help y id5tify x & also include in=mation on :]e ! rock or m9]al c be f\nd 9 ,texas1 "s ( its uses1 & h[ x may h =m$4 ,! *>t on page #ii li/s *emical composition1 specific gravity1 & h>dness ( v>i\s ,texas m9]als4 ,agate4 ,see ,qu>tz4 ,agatiz$ ,wood4 ,see ,qu>tz4 ,alaba/]4 ,see ,gypsum4 ,albite4 ,see ,feldsp>4 ,alm&ite4 ,see ,g>net4 ,ame?y/4 ,see ,qu>tz4 ,amphibole ,asbe/os4 ,see ,asbe/os4 ,anhydrite ,anhydrite1 calcium sulfate1 is a r s(t m9]al t y c scrat* ) a pocket knife1 al?\gh n ) a f+]nail4 ,x has a glassy or a pe>ly lu/] & is transp>5t or transluc5t4 ,mo/ anhydrite is :ite1 b impurities cause x to be grayi%1 blui%1 or r$di%4 ,:5 rubb$ across a /reak plate1 anhydrite gives a :ite /reak4 ,?is m9]al has an unev5 fracture1 & x cleaves 9 ?ree directions t are at "r angles to ea* o!r4 ,x commonly occurs z rectangul> cleavage fragm5ts or z sug>y cry/all9e masses4 ,anhydrite resembles dolomite1 lime/one1 or gypsum4 ,y c use a h>dness te/ to di/+ui% x f gypsum 7anhydrite is h>d]7 & an acid te/ to di/+ui% x f lime/one & dolomite4 ,a drop ( dilute hydro*loric acid w fizz :5 y put x on lime/one or p[d]$ dolomite4 ,on anhydrite1 ! acid does n fizz4 ,illu/ration3 ,massive anhydrite4 ,anhydrite occurs at sev]al places 9 ,texas4 ,x is1 = example1 se5 9 bluffs along ! ,d\ble ,m\nta9 ,=k & ! ,salt ,=k ( ! ,brazos ,riv] 9 nor?-c5tral ,texas4 ,mo/ ( ! ,texas anhydrite1 h[ev]1 occurs und]gr\nd4 ,9 ! ,gulf ,coa/al ,pla91 ! anhydrite is f\nd bel[ ! surface 9 salt domes4 7,salt domes are describ$ ) halite on p4 #ff & ) sulfur on p4 #ia47 ,ano!r anhydrite locality is 9 ! subsurface ,p]mian bas9 ( we/ ,texas4 ,oil wells drill$ 9 ?is bas9 p5etrate great1 ?ick deposits ( massive anhydrite4 ,! anhydrite 0 deposit$ dur+ ! ,p]mian ,p]iod f a sea t cov]$ ?is area4 ,z ! sea gradually evaporat$1 ! m9]al matt] t 0 dissolv$ 9 x came out ( solution to =m anhydrite1 halite1 & sev]al o!r m9]als4 ,antigorite4 ,see ,s]p5t9e4 ,arg5tite4 ,see ,silv] ,m9]als4 ,asbe/os ,asbe/os is n really any "o p>ticul> m9]al4 ,x is ! "n giv5 to sev]al m9]als t occur 9 masses ( sl5d]1 delicate fib]s4 ,9 ! m typical k9ds ( asbe/os1 ^! fib]s--:5 pull$ ap>t--resemble s(t1 fluffy1 silk /r+s4 ,sev]al small deposits ( amphibole asbe/os h be5 f\nd 9 ! ,llano uplift area ( c5tral ,texas4 ,?is asbe/os is a v>iety ( ! m9]al tremolite1 a calcium-magnesium silicate4 ,x has fib]s t break r easily1 & x has a silky lu/]4 ,x is a %ade ( gre5 or gray & gives a :ite /reak :5 rubb$ across a /reak plate4 ,:5 y pull its fib]s ap>t1 y actually are break+ ! m9]al along its two directions ( p]fect cleavage4 ,?is amphibole asbe/os is s(t] ?an o!r v>ieties ( ! m9]al tremolite--a copp] p5ny scrat*es x easily4 ,illu/ration3 ,gre5i%1 silky amphibole asbe/os f nor!a/]n ,gillespie ,c\nty1 ,texas4 ,! asbe/os occurs 9 ve9s 9 ,precambrian metamorphic rocks 9 s\!rn ,llano ,c\nty1 nor?we/]n ,blanco ,c\nty1 & nor!a/]n ,gillespie ,c\nty4 ,^! deposits are small4 ,a v>iety ( ! m9]al s]p5t9e call$ *rysotile asbe/os is ! k9d mo/ us$ by indu/ry4 ,its fib]s are commonly flexible en\gh & /rong en\gh to be wov5 into clo?4 ,?is clo? is made into articles1 su* z firepro( suits1 gloves1 & !at] curta9s4 ,"s *rysotile has be5 f\nd 9 ,precambrian metamorphic rocks 9 nor?we/]n ,blanco ,c\nty1 b x does n break into fib]s f9e en\gh or flexible en\gh to be call$ asbe/os4 ,azurite4 ,see ,copp] ,m9]als4 ,b>ite ,b>ite1 b>ium sulfate1 is a fairly common m9]al 9 ,texas4 ,x has a glassy or a pe>ly lu/]1 & x is transp>5t to transluc5t4 ,b>ite is colorless1 :ite1 br[ni%1 blui%1 yell[i%1 or r$di%4 ,:5 rubb$ across a /reak plate1 x gives a :ite /reak4 ,x is n extremely h>d--y c scrat* x ) a pocket knife1 al?\gh n ) a f+]nail4 ,b>ite is di/9ctive because ( its weight & cleavage4 ,x cleaves 9 ?ree directions1 & "s cleavage fragm5ts are flat or platy4 ,= a m9]al ) a nonmetallic lu/]1 b>ite is heavy--x has a specific gravity ( #d4e4 ,illu/ration3 ,b>ite cleavage fragm5t f we/ ,texas4 ,b>ite commonly occurs z prism-%ap$ & z flat cry/als1 z granul> masses1 z cleavable masses1 & z r\nd$ masses call$ nodules4 ,9 ,texas1 "s ( x 0 deposit$ 9 s$im5t>y rocks by und]gr\nd wat]s4 ,z ! wat]s seep$ ?r\gh ^! rocks1 m9]al matt] came out ( solution to =m ! b>ite4 ,"s ( ! b>ite 9 ,texas also =m$ f solutions t came f hot magmas4 ,a numb] ( b>ite deposits h be5 f\nd 9 ,texas1 b _m ( !m are small4 ,b>ite occurs 9 ,precambrian metamorphic rocks 9 ,gillespie & ,llano c\nties1 9 ,p5nsylvanian %ale 9 ,brew/] ,c\nty1 9 ,p]mian %ales 9 ,baylor & ,taylor c\nties1 & 9 ,p]mian lime/ones 9 ,culb]son ,c\nty4 ,x is f\nd 9 ,triassic r$ %ales 9 ,h[>d ,c\nty & 9 ,cretace\s s$im5t>y rocks 9 ,brew/]1 ,br[n1 ,hudspe?1 ,jeff ,davis1 ,k9ney1 & ,val ,v]de c\nties4 ,9 ,live ,oak ,c\nty1 b>ite occurs 9 ,t]ti>y b5tonitic clays4 ,b>ite is be+ m9$ f a deposit 9 ! ,sev5 ,he>t ,gap area nor!a/ ( ,van ,horn 9 ,culb]son ,c\nty4 ,b>ite is us$ 9 a numb] ( ways4 ,x is a s\rce ( b>ium *emicals1 & x also is p[d]$ & us$ z an +r$i5t 9 pa9t4 ,! oil indu/ry uses l>ge am\nts ( b>ite4 ,9 drill+ = oil by ! rot>y me?od1 wat] & muds are pump$ d[n ! hole to aid drill+4 ,b>ite is add$ to ^! drill+ fluids to make !m heavy1 s9ce high-pressure gases are n z likely to bl[ heavy fluids out ( ! hole4 ,basalt ,basalt is a heavy igne\s rock t is black1 d>k gray1 or d>k br[n4 ,?is rock is made up *iefly ( a feldsp> m9]al1 su* z labradorite1 & a pyrox5e m9]al1 su* z augite4 ,o!r m9]als may be pres5t4 ,! m9]al gra9s ( "s basalts are s small t y _c di/+ui% !m ev5 ) a magnify+ glass4 ,o!r basalts1 h[ev]1 are porphyritic1 :i* means t !y conta9 l>g]1 easily se5 cry/als & gra9s ( feldsp> & pyrox5e scatt]$ ei!r ?r\gh a mass ( ! small m9]al gra9s or ?r\gh glassy mat]ial4 ,"s basalts conta9 _m small holes4 ,^! holes1 call$ vesicles1 7 =m$ :5 bubbles ( gas 7 trapp$ 9 ! h>d5+ magma4 ,lat]1 solutions mov+ ?r\gh ! rocks may h deposit$ ano!r m9]al--su* z calcite or *alc$ony--9 "s ( ! vesicles4 ,basalt =ms f molt5 rock mat]ial t h>d5s ei!r on or b5ea? ! surface--x c be extrusive or intrusive4 ,mu* ( ! basalt n[ f\nd 9 ! ,trans-,pecos c\ntry ( we/ ,texas =m$ f lava t fl[$ out onto ! surface dur+ ! ,t]ti>y ,p]iod4 ,a few ( ! places :]e basalt occurs 9 we/ ,texas are ! ,*9ati ,m\nta9s ( ,presidio ,c\nty1 ! ,*isos ,m\nta9s ( ,brew/] ,c\nty1 ! ,davis ,m\nta9s ( ,jeff ,davis ,c\nty1 & ! ,van ,horn ,m\nta9s ( ,culb]son & ,hudspe? c\nties4 ,illu/ration3 ,basalt f ,brew/] ,c\nty1 ,texas4 ,sev]al v>ieties ( basalt occur 9 ! ,balcones fault region ( ,b&]a1 ,comal1 ,hays1 ,k9ney1 ,m$9a1 ,travis1 & ,uvalde c\nties4 ,^! basalts =m$ f molt5 magma t =c$ its way into rocks j bel[ ! e>?'s surface4 ,"s basalt1 :i* is kn[n comm]cially z trap rock1 is produc$ 9 ,uvalde ,c\nty4 ,x is cru%$ & us$ = railroad balla/1 road build+ mat]ial1 & z concrete aggregate4 ,b5tonite4 ,see ,clay4 ,biotite4 ,see ,mica4 ,braunite4 ,see ,manganese ,m9]als4 ,calcite ,calcite1 calcium c>bonate1 is "o ( ! mo/ abundant m9]als 9 ,texas4 ,x is ! *ief m9]al 9 lime/one & 9 "s m>ble4 ,x also s]ves z ! cem5t+ mat]ial 9 _m s&/ones4 ,cry/als1 gra9s1 & cleavable masses ( calcite1 :i* h be5 deposit$ by und]gr\nd wat]1 occur 9 cracks & cavities 9 _m ( ! igne\s1 metamorphic1 & s$im5t>y rocks ( ,texas4 ,calcite also occurs z cave1 spr+1 & /ream deposits & z cali*e4 ,calcite is transp>5t or transluc5t1 &--dep5d+ on ! v>iety--its lu/] is glassy to e>?y4 ,mo/ calcite is :ite or colorless1 b x c be a %ade ( p9k1 blue1 gre51 br[n1 yell[1 or gray4 ,x gives a :ite /reak :5 y rub x across a /reak plate4 ,two prop]ties ( calcite to notice are ! h>dness & ! cleavage4 ,?is m9]al cleaves p]fectly 9 ?ree directions t are n at "r angles to ea* o!r1 & "s ( ! cleavage fragm5ts are rhomboh$rons4 ,calcite is r s(t--y c scrat* x ) a copp] p5ny b n ) a f+]nail4 ,a drop or two ( dilute hydro*loric acid also w help y to id5tify ?is m9]al4 ,! acid w readily fizz & bubble :5 x is plac$ on calcite4 ,illu/ration3 ,calcite has p]fect rhomboh$ral cleavage4 ,! ?ree directions ( cleavage are n at "r angles to ea* o!r4 ,calcite occurs 9 m diff]5t k9ds ( cry/al %apes ?an any o!r m9]al4 ,"s ( ^! cry/als are flat & tabul>2 "s are rhomboh$rons2 "s are prisms4 ,po9t$ cry/als1 call$ dog-too? sp>1 & tw9n$ cry/als h be5 f\nd 9 ! ,t]l+ua area ( ,brew/] ,c\nty 9 we/ ,texas4 ,a some:at unusual occurr5ce ( calcite cry/als is 9 geodes4 ,"s ( ^! are f\nd 9 ,l[] ,cretace\s rocks we/ ( ,au/9 9 ,travis ,c\nty4 ,transp>5t cry/als & cleavage fragm5ts ( calcite %[ a prop]ty call$ d\ble refraction 7o!r m9]als %[ x1 too74 ,to te/ ?is prop]ty1 y c m>k a s+le dot on pap]4 ,:5 y look at ! dot ?r\gh a piece ( cle> calcite1 y w see two dots in/ead ( "o4 ,?is happ5s because a ray ( light is b5t 7refract$7 & is split into two rays z x ent]s ! m9]al4 ,^! two rays travel ?r\gh ! calcite 9 slightly diff]5t directions1 & ea* c>ries an image ( ! dot ?r\gh ! m9]al4 ,! two images t y see are at ! po9ts :]e ! two rays leave ! calcite4 ,calcite t is deposit$ at spr+s1 along riv] & creek banks1 & 9 caves is kn[n z trav]t9e4 ,cave =ms ( trav]t9e1 includ+ /alagmites & /alactites1 occur 9 sev]al caves 9 ,texas4 ,ano!r k9d ( trav]t9e is call$ calc>e\s tufa or calc>e\s s9t]4 ,x is a por\s & spongy-look+ mat]ial deposit$ f wat] c>ry+ dissolv$ lime/one & is f\nd ar\nd ! op5+s ( "s spr+s & along "s creek & riv] banks4 ,a dull1 e>?y calcite deposit1 kn[n z cali*e1 occurs 9 areas ( ,texas t h scant ra9fall1 su* z ! ,high ,pla9s1 we/ ,texas1 & ! s\?we/]n "p ( ! ,gulf ,coa/al ,pla94 ,cali*e commonly is f\nd mix$ ) o!r mat]ials1 su* z clay1 s&1 or gravel4 ,?is sub/ance may be firm & compact or loose & p[d]y4 ,x is ?\ght t cali*e =ms :5 gr\nd moi/ure1 conta9+ dissolv$ calcium bic>bonate1 moves upw>d4 ,9 dry areas ( ! c\ntry1 ?is moi/ure evaporates4 ,z x does1 x leaves a cru/ ( calcium c>bonate 9 ! =m ( cali*e on or ne> ! surface ( ! gr\nd4 ,illu/ration3 ,calcite cry/als 7dog-too? sp>7 f ! ,t]l+ua area ( ,brew/] ,c\nty1 ,texas4 ,cali*e is qu>ri$ 9 _m c\nties 9 ,texas & is us$ *iefly z road mat]ial & z an aggregate4 ,cali*e4 ,see ,calcite4 ,c>notite4 ,see ,uranium ,m9]als4 ,cassit]ite ,cassit]ite1 t9 dioxide1 is ! m9]al t s]ves z ! *ief s\rce ( t94 ,t9 does n corrode & t>ni%1 & "o ( its ma9 uses is 9 ! mak+ ( t9 cans4 7,actually1 our t9 cans are made f ?9 %eets ( /eel t h be5 coat$ ) a protective lay] ( t947 ,cassit]ite has ei!r a nonmetallic or a submetallic lu/]4 ,"s specim5s are brilliant & %9y2 o!rs are dull4 ,cassit]ite may be transluc5t to transp>5t4 ,x may be black1 br[n1 gray1 r$di% br[n1 or yell[i% br[n4 ,:5 rubb$ across a /reak plate1 ?is m9]al leaves a pale br[n1 a pale yell[1 or a :ite /reak4 ,cassit]ite is q heavy--x has a specific gravity ( #f4h to #g4a4 ,x is too h>d to be scrat*$ by an av]age pocket knife4 ,sometimes1 prospectors use a *emical te/ to help !m id5tify cassit]ite4 ,!y put small pieces ( metallic z9c into a j> or te/ tube conta9+ dilute hydro*loric acid4 ,!n !y add a few fragm5ts ( ! m9]al t !y suspect is cassit]ite4 ,if ! fragm5ts are cassit]ite1 !y become cov]$ ) a pale gray coat+ ( metallic t94 ,cassit]ite's mo/ common cry/al %ape is a %ort1 #h-sid$ prism ) pyramids at ea* end1 b p]fect cry/als are n (t5 f\nd4 ,mo/ ,texas cassit]ite does n %[ a cry/al %ape4 ,in/ead1 x occurs z cry/all9e masses 9 igne\s rocks & z loose pebbles t h wea!r$ out ( ^! rocks4 ,cassit]ite occurs 9 a numb] ( places 9 ! ,unit$ ,/ates b n 9 l>ge quantities4 ,a small am\nt ( cassit]ite has be5 f\nd 9 qu>tz ve9s 9 ,precambrian granite 9 bo? c5tral ,texas & we/ ,texas4 ,9 ,el ,paso ,c\nty1 ! cassit]ite is f\nd on ! ea/ side ( ! ,frankl9 ,m\nta9s a few miles nor? ( ,el ,paso1 :]e "s ( x has be5 m9$4 ,9 c5tral ,texas1 cassit]ite occurs 9 ! ,/reet] area ( ,mason ,c\nty4 ,:5 ! granite rocks 9 ^! areas 7 =m$1 probably n all ( ! hot magmas cool$ & h>d5$ at ! same "t4 ,! fluids giv5 (f by ! rema9+ magmas conta9$ t9 & sev]al o!r elem5ts4 ,x is believ$ t ^! fluids mov$ up into cracks 9 ! granite rocks & =m$ ! cassit]ite4 ,cele/ite ,cele/ite is a /rontium sulfate m9]al4 ,x is colorless1 :ite1 yell[1 or gray4 ,light blue specim5s ( ?is m9]al also are f\nd1 & x is because ( ?is sky-l color t cele/ite gets its "n4 ,! ^w cele/ite comes f ! ,lat9 ^w caele/is1 mean+ ( ! sky4 ,cele/ite has a glassy to a pe>ly lu/]1 & x is ei!r transp>5t or transluc5t4 ,x gives a :ite /reak :5 rubb$ across a /reak plate4 ,cele/ite has a specific gravity ( #c4ie to #c4ig4 ,x is1 h[ev]1 light] ?an b>ite1 a m9]al t x resembles4 ,cele/ite is n v h>d--a knife w scrat* x1 al?\gh y\r f+]nail w n4 ,x cleaves 9 ?ree directions1 & "s ( ! fragm5ts are flat & slabby4 ,illu/ration3 ,cele/ite cleavage fragm5t f ,lampasas ,c\nty1 ,texas4 ,cele/ite occurs commonly ei!r z prism-%ap$ or flat cry/als & z cleavable1 granul>1 or fibr\s cry/all9e masses4 ,9 ,texas1 x is f\nd 9 geodes1 z r\nd$ nodules1 or z b$d$ or lay]-l deposits 9 lime/ones & o!r s$im5t>y rocks4 ,9 ,real ,c\nty1 cele/ite occurs on ! walls ( a cave 9 ,cretace\s lime/one4 ,"s cele/ite may be deposit$ by sea wat]1 b mu* ( ! ,texas cele/ite is believ$ to h be5 deposit$ by und]gr\nd wat] t seep$ ?r\gh cracks & pores 9 ! lime/ones & o!r s$im5t>y rocks4 ,?is wat] pick$ up & dissolv$ /rontium comp\nds t 7 scatt]$ 9 small am\nts ?r\gh ! rocks4 ,!n1 x re-deposit$ ! /rontium 9 ! rocks z cele/ite4 ,9 ,texas1 b$s ( cele/ite occur 9 ,p]mian rocks 9 ,coke1 ,fi%]1 & ,nolan c\nties & 9 ,l[] ,cretace\s rocks 9 ,br[n1 ,coman*e1 & ,mills c\nties4 ,cele/ite geodes & nodules are f\nd 9 ,l[] ,cretace\s lime/one rocks 9 ,lampasas1 ,travis1 & ,williamson c\nties1 & 9 ,p]mian rocks 9 ,coke1 ,fi%]1 ,nolan1 & ,taylor c\nties4 ,cele/ite is "o ( two m9]als 7! o!r m9]al is /rontianite1 /rontium c>bonate7 us$ z a s\rce ( /rontium4 ,/rontium comp\nds give a crimson-r$ color to a flame1 s !y are us$ 9 fireworks1 trac] bullets1 & fl>es4 ,p]haps y h se5 a r$ fl>e set out on ! highway at night to w>n motori/s t a truck has /all$4 ,! *ances are good t ! fl>e's r$ flame 0 due to a /rontium comp\nd4 ,"s ( ! ,texas cele/ite has be5 m9$1 b mo/ ( ! /rontium m9]als n[ us$ 9 ! ,unit$ ,/ates are import$ f ,engl& & ,mexico4 ,c]>gyrite4 ,see ,silv] ,m9]als4 ,*alc$ony4 ,see ,qu>tz4 ,*alcocite4 ,see ,copp] ,m9]als4 ,*alcopyrite4 ,see ,copp] ,m9]als4 ,*alk4 ,see ,lime/one4 ,*]t 7,fl9t74 ,see ,qu>tz4 ,*rysotile4 ,see ,asbe/os2 ,s]p5t9e4 ,c9nab> ,c9nab>1 :i* is m]curic sulfide1 is ! mo/ common m]cury m9]al4 ,x has a d>k r$ or a bright yell[i%-r$ color & is transp>5t to transluc5t4 ,:5 rubb$ across a /reak plate1 x leaves a d>k r$ /reak4 ,if pure1 c9nab> has a brilliant1 %9y1 nonmetallic lu/]4 ,x is1 h[ev]1 commonly f\nd mix$ ) impurities1 su* z clay1 calcite1 iron oxide1 or bitum9\s mat]ial1 & !n x looks dull & e>?y4 ,c9nab> is q heavy--x has a specific gravity ( #h4aj4 ,x is r s(t1 & y c scrat* x ) a copp] p5ny4 ,"s prospectors use a quick *emical te/ to id5tify c9nab>4 ,!y rub a clean1 %9y copp] co9 ) a m9]al sample t has be5 moi/5$ ) a drop or two ( dilute hydro*loric acid4 ,if ! sample is c9nab>1 a light silv]y-gray coat+ appe>s on ! co94 ,c9nab> occurs z small cry/als or z f9e-gra9$ or compact cry/all9e masses4 ,x is f\nd 9 ve9s t fill cracks 9 rocks & also occurs z cru/s & coat+s on rocks4 ,x also may be widely scatt]$ ?r\gh rocks1 su* z lime/ones4 ,c9nab> occurs 9 ! ,t]l+ua area ( ,brew/] & ,presidio c\nties 9 we/ ,texas4 ,x has be5 m9$ !re1 (f & on1 s9ce ab\t #ahid1 & dur+ ?is "t1 m]cury wor? _m millions ( doll>s has be5 produc$4 ,mo/ ( ?is we/ ,texas c9nab> is f\nd 9 cracks1 pores1 & breccia-fill$ cavities ( ,cretace\s lime/ones & clays4 ,if y w look at ! ,texas geologic map 7pp4 #d-e71 y w see t igne\s rocks occur 9 ?is di/rict4 ,_m millions ( ye>s ago dur+ ! ,t]ti>y ,p]iod1 :5 ^! igne\s rocks 7 /ill hot magma1 "s ( !m pu%$ up "u ! ,cretace\s rocks & emitt$ fluids conta9+ m]cury4 ,! fluids mov$ upw>d ?r\gh cracks & pores 9 ! ,cretace\s rocks :]e !y deposit$ ! m]cury z c9nab> & z o!r m]cury m9]als4 ,illu/ration3 ,c9nab> cry/als 7d>k7 ) calcite cry/als 7:ite7 f ! ,t]l+ua area ( ,brew/] ,c\nty1 ,texas4 ,m]cury is an unusual elem5t4 ,in/ead ( occurr+ z a solid metal at ord9>y room temp]atures1 z d gold1 silv]1 & lead1 x rema9s a liquid until x is cool$ to #ch degrees bel[ z]o ,fahr5heit4 ,because ! silv]y little drops ( liquid m]cury roll ab\t z if !y 7 alive1 ?is elem5t long has be5 call$ quicksilv]4 ,m]cury is us$ 9 a v>iety ( ways4 ,9 "s noiseless light-swit*es1 a glass tube conta9+ a small ball ( m]cury tilts :5 ! swit* is turn$ 8on40 ,! m]cury !n rolls to ! end ( ! tube t conta9s electrical contacts & quietly completes ! electrical circuit4 ,9 o!r uses1 m]cury is add$ to silv]1 t91 & o!r metals to make fill+s = tee?4 ,"s m$ic9es1 su* z calomel & m]curo*rome1 conta9 m]cury4 ,fulm9ate ( m]cury helps to set (f dynamite & o!r explosives4 ,m]cury is us$ 9 _m b>omet]s & !rmomet]s1 & f>m]s use m]cury poisons to control insects & fungi4 ,m]cury also commonly is us$ to obta9 gold f its ores4 ,"o me?od ( accompli%+ ?is is to pass wet gold-be>+ gravel or cru%$ rock ov] metal plates t are coat$ ) m]cury4 ,! gold p>ticles quickly mix ) ! m]cury to =m an amalgam1 :i* lat] c be scrap$ (f ! plates4 ,! gold is !n recov]$ by heat+ ! amalgam to drive (f ! m]cury4 ,clay ,clay is a smoo?1 s(t1 e>?y rock made up ( m9]al p>ticles no bigg] ?an specks ( du/4 ,"s ( ! p>ticles are clay m9]als1 :i* consi/ ( alum9um1 silicon1 & o!r elem5ts4 ,9 addition1 t9y p>ticles ( qu>tz1 calcite1 & o!r m9]als may also be pres5t 9 ! clay4 ,! clay p>ticles are all t rema9 ( rocks & ( m9]als1 su* z feldsp>1 t h be5 brok5 into fragm5ts or alt]$ into clay m9]als by wea!r+4 ,"s clay rema9s at ! place :]e x =m$1 b "s is c>ri$ away & deposit$ else:]e4 ,clay is :ite1 tan1 br[n1 r$1 gre51 blue1 gray--almo/ any color4 ,:5 moi/1 x has an e>?y odor4 ,y c moi/5 a piece ( clay en\gh to notice ?is j by brea?+ on x4 ,mo/ clays1 :5 wet1 c be mold$ into _m diff]5t %apes--t is1 !y are pla/ic1 b :5 !y are dry1 !y are firm & solid4 ,clay is abundant 9 ,texas & has a numb] ( uses4 ,"s goes to make portl& cem5t1 & "s is bak$ or burn$ 9 a kiln to make brick1 tile1 sew] pipes1 pott]y1 & o!r products4 ,?is k9d ( clay is obta9$ f ,t]ti>y =mations ( ! ,gulf ,coa/al ,pla91 f ,upp] ,cretace\s =mations 9 c5tral ,texas1 & f ,p5nsylvanian =mations 9 nor?-c5tral ,texas4 7,y c locate ,t]ti>y1 ,cretace\s1 & ,p5nsylvanian rocks on ! ,texas geologic map1 pp4 #d-e47 ,a special k9d ( :ite burn+ clay t c be us$ to make *9aw>e is call$ kaol9 or *9a clay4 ,x conta9s p>ticles ( ! clay m9]al kaol9ite z well z sev]al o!r clay m9]als4 ,deposits ( *9a clay occur 9 s\!rn ,jeff ,davis ,c\nty & 9 ,real ,c\nty ne> ,leakey1 b none is be+ produc$4 ,ano!r k9d ( clay1 b5tonite1 =ms f wea!r$ volcanic a%4 ,b5tonite conta9s ! clay m9]al montmorillonite & looks smoo? & soap-l4 ,fre% samples ( ?is clay are :ite1 pale gre51 or pale blue1 b dri$-out or wea!r$ samples are tan1 br[n1 yell[1 or r$di%4 ,:5 wet1 b5tonite absorbs wat]1 swells1 & !n has a jelly-l appe>ance4 ,surface deposits ( b5tonite occur *iefly 9 ,eoc5e ,t]ti>y =mations ( ! ,gulf ,coa/al ,pla91 9 ,cretace\s =mations ( ! ,big ,b5d area ( we/ ,texas1 & 9 ,quat]n>y =mations ( ! ,high ,pla9s4 ,illu/ration3 ,b5tonite is us$ z a drill+-fluid additive 9 ! rot>y me?od ( drill+ = petroleum & gas4 ,"s b5tonite is us$ to absorb unwant$ color+ mat]ial 9 petroleum & 9 vegetable oils4 ,x is !n kn[n z a blea*+ clay4 ,b5tonite blea*+ clay is obta9$ f "s ( ! ,t]ti>y =mations along ! ,texas ,gulf ,coa/al ,pla94 ,x has be5 produc$ 9 ,angel9a1 ,fayette1 ,gonzales1 ,jasp]1 ,walk]1 & o!r c\nties 9 ?is area4 ,ano!r important use ( b5tonite1 & ( o!r clay1 too1 is z drill+ mud4 ,9 ! rot>y me?od ( drill+ = oil & gas1 mud is pump$ d[n into ! drill$ hole4 ,?is mud c>ries ! rock cutt+s up to ! surface1 x cools ! drill+ tools1 & x coats & seals ! walls ( ! hole4 ,along ! ,gulf ,coa/al ,pla91 drill+ clay is obta9$ f ,t]ti>y =mations4 ,common ,opal4 ,see ,opal4 ,copp] ,m9]als 7,*alcocite1 ,*alcopyrite1 ,mala*ite1 ,azurite7 ,a numb] ( m9]als conta9+ copp]1 su* z *alcocite1 *alcopyrite1 mala*ite1 & azurite1 occur 9 small deposits 9 ,texas4 ,!y are f\nd *iefly 9 ! ,llano uplift area ( c5tral ,texas1 9 ! ,van ,horn area ( ,culb]son & ,hudspe? c\nties 9 we/ ,texas1 & 9 a gr\p ( c\nties 9 nor?-c5tral ,texas4 ,copp] is an important elem5t4 ,because x is an unusually good conductor ( electricity 7only silv]1 :i* co/s mu* m1 is a bett] "o71 x is us$ = _m k9ds ( wires = swit*bo>ds1 g5]ators1 motors1 telephone & telegraph equipm5t1 & light & p[] l9es4 ,manufactur]s commonly comb9e copp] ) o!r elem5ts4 ,= example1 "s copp] is mix$ ) z9c to make brass & ) t9 & a little z9c to make bronze4 ,^! mixtures are call$ alloys4 ,_m products are made f copp] alloys1 includ+ tub+1 pipes1 jewelry1 pots1 & pans4 ,ev5 our co9s conta9 copp]4 ,sometimes1 a prospector uses a *emical te/ to f9d out if copp] is pres5t 9 a m9]al4 ,fir/1 he cru%es a small sample ( :at he believes is a copp] m9]al 7su* z *alcocite1 *alcopyrite1 azurite1 or mala*ite74 ,he !n puts ! sample 9 a glass j> or te/ tube & p\rs 9 a small am\nt ( dilute nitric acid 7?is acid1 l hydro*loric acid1 is poison\s74 ,aft] ! sample has dissolv$ 9 ! acid1 he adds en\gh ammonium hydroxide to make ! solution alkal9e4 ,if ! sample is a copp] m9]al1 ! solution turns a deep-blue color4 ,"o ( ! copp] m9]als1 *alcocite1 copp] sulfide1 also is kn[n z copp] glance4 ,x is a metallic m9]al t commonly t>ni%es to a dull black4 ,by *ipp+ (f a fragm5t to obta9 a fre% surface1 y w see t x has a %9y lead-gray color4 ,*alcocite is r s(t1 & x is sectile1 t is1 a knife w cut ?r\gh x z well z scrat* x4 ,:5 y rub *alcocite across a /reak plate1 x gives a grayi%-black /reak4 ,?is m9]al commonly occurs z compact masses or z granul> masses4 ,*alcocite1 ) its d>k color1 does n look at all l copp]1 :i* is a bright r$di% br[n4 ,*alcocite1 h[ev]1 is ! *ief copp] m9]al at ! mo/ important copp] m9e 9 ,texas1 ! ,hazel m9e1 :i* is ab\t #ae miles nor?we/ ( ,van ,horn 9 ,culb]son ,c\nty 9 we/ ,texas4 ,?is m9e1 al?\gh n[ idle & almo/ fill$ ) wat]1 has produc$ ab\t "o & a half million p\nds ( copp] along ) m valuable silv] ores4 ,"h1 ! *alcocite & o!r m9]als occur 9 mat]ial t fills l>ge cracks 9 r$ s&/one ( ! ,precambrian ,hazel ,=mation4 ,x is ?\ght t long ago1 molt5 igne\s rock mat]ial f> bel[ ! surface s5t out hot solutions conta9+ copp] & o!r elem5ts4 ,^! solutions mov$ upw>d & deposit$ m9]als 9 ! fracture zone 9 ! s&/one4 ,*alcocite occurs also 9 nor?-c5tral ,texas4 ,x is f\nd 9 ,ar*]1 ,baylor1 ,clay1 ,fo>d1 ,h>deman1 ,k+1 ,knox1 ,/onewall1 & sev]al o!r c\nties ( ?is area4 ,"h1 x occurs 9 ,p]mian s$im5t>y rocks 7call$ 8r$ b$s07 z r\nd$ masses1 z scatt]$ gra9s1 & z petrifi$ wood4 ,because ^! deposits are f> f any igne\s rocks1 !y app>5tly did n =m 9 ! same way z ^? at ! ,hazel m9e4 ,^! nor?-c5tral ,texas deposits h nev] really be5 comm]cially develop$4 ,dur+ ! ,civil ,w>1 h[ev]1 "s copp] f ?is area 0 made into p]cussion caps = ! ,conf$]acy4 ,illu/ration3 ,! ,hazel copp]-silv] m9e1 ,culb]son ,c\nty1 ,texas1 z x appe>$ 9 #aiea4 ,photograph by ,p4 ,t4 ,flawn4 ,ano!r copp] m9]al1 *alcopyrite1 is a copp]-iron sulfide4 ,x also is kn[n z copp] pyrites & yell[ copp] ore4 ,?is m9]al has a metallic lu/] & a brass-yell[ or a gold5-yell[ color4 ,:5 rubb$ across a /reak plate1 x gives a gre5i%-black /reak4 ,*alcopyrite w t>ni% & !n has bronze1 blue1 purple1 & o!r ra9b[-l colors4 ,?is m9]al is fairly s(t--y c scrat* x ) a pocket knife4 ,because ( *alcopyrite's yell[ color1 x has (t5 be5 mi/ak5 = gold4 ,= ?is reason1 x1 l iron pyrite1 is (t5 call$ fool's gold4 7,see ,gold1 p4 #fj1 = ways to tell !m ap>t47 ,*alcopyrite commonly is f\nd 9 compact masses t %[ no cry/al %apes4 ,^! masses ei!r are scatt]$ ?r\gh rocks or occur 9 mat]ial t fills cracks 9 rocks4 ,"s *alcopyrite is f\nd 9 ,precambrian s&/one at ! ,hazel m9e & 9 o!r deposits 9 ! ,van ,horn area ( ,culb]son & ,hudspe? c\nties4 ,x also occurs 9 ,precambrian rocks at ! ,%]idan & ,pavitte prospects 9 ,burnet ,c\nty4 ,^! *alcopyrite localities are 9 di/ricts :]e igne\s rocks occur4 ,x is likely t1 long ago1 hot solutions conta9+ copp] mov$ upw>d1 out ( deeply buri$ molt5 magma4 ,:ile /ill f> bel[ ! surface1 ! solutions deposit$ ! *alcopyrite 9 cracks & o!r op5+s 9 ! ne>by rocks4 ,two copp] m9]als ( ,texas1 azurite & mala*ite1 are copp] c>bonates4 ,azurite is commonly call$ *essylite & blue copp]2 mala*ite is call$ gre5 copp] c>bonate4 ,because ^! m9]als are c>bonates1 a drop ( dilute hydro*loric acid w fizz & bubble :5 plac$ on ei!r ( !m4 ,azurite has a bright1 int5se blue color & leaves a blue /reak :5 rubb$ across a /reak plate4 ,mala*ite has a bright gre5 color & leaves a gre5 /reak4 ,^! m9]als h a nonmetallic lu/] & a glassy to dull appe>ance4 ,commonly1 !y are transluc5t1 al?\gh "s specim5s ( azurite are transp>5t4 ,bo? azurite & mala*ite are fairly s(t--a pocket knife w scrat* !m1 b a copp] p5ny w n4 ,azurite & mala*ite occur z individual cry/als1 b y are m likely to f9d !m z cru/s on rocks & on o!r m9]als4 ,mala*ite is also f\nd 9 r\nd$ fibr\s masses t resemble bun*es ( grapes 7describ$ !n z botryoidal74 ,bo? azurite & mala*ite are =m$ 9 ! same way4 ,und]gr\nd wat]s seep ?r\gh rocks t conta9 deposits ( copp] m9]als 7su* z *alcocite & *alcopyrite7 & cause *emical reactions :i* *ange ^! m9]als into mala*ite & azurite4 ,mala*ite is m pl5tiful ?an azurite1 b bo? m9]als c be f\nd toge!r4 ,y c expect to f9d at lea/ "o ( !m at ! same localities :]e *alcocite1 *alcopyrite1 & o!r copp] m9]als occur4 ,coqu9a4 ,see ,lime/one4 ,diatomite4 ,see ,opal4 ,dolomite ,dolomite is ! "n giv5 bo? to a rock & to a m9]al4 ,! m9]al is a calcium-magnesium c>bonate & has a glassy or a pe>ly lu/]4 ,x is any ( a numb] ( colors1 su* z :ite1 p9k1 br[n1 or gray1 or x c be colorless4 ,dolomite leaves a :ite /reak on a /reak plate & is transp>5t to transluc5t4 ,x is n p>ticul>ly h>d & c be scrat*$ ) a pocket knife1 al?\gh n ) a copp] p5ny4 ,dolomite cleaves p]fectly 9 ?ree directions1 & "s ( ! cleavage fragm5ts are rhomboh$rons4 ,h[ev]1 ! cleavages ( ! individual m9]al gra9s 9 specim5s ( f9e-gra9$ massive dolomite are n readily di/+ui%able4 ,illu/ration3 ,dolomite rock f ! vic9ity ( ,fairl&1 ,burnet ,c\nty1 ,texas4 ,mo/ ,texas dolomite occurs z co>se-1 m$ium-1 & f9e-gra9$ cry/all9e masses z ! *ief m9]al 9 dolomite rock & 9 dolomitic m>ble4 ,x is also f\nd z #f-sid$ cry/als t are rhomb-%ap$2 :5 ! faces are curv$1 !y h a saddle-l appe>ance4 ,cry/als ( ! m9]al dolomite commonly occur 9 cavities 9 ! dolomite rocks4 ,x is believ$ t !y 7 deposit$ !re by seep+ und]gr\nd wat]s4 ,! wat]s dissolv$ "s ( ! dolomite 9 ! rocks & !n re-deposit$ x z cry/als4 ,dolomite rock is made up mo/ly ( cry/all9e gra9s ( ! m9]al dolomite4 ,9 addition1 qu>tz gra9s1 calcite1 & o!r m9]als may be pres5t4 ,dolomite rock is almo/ any color--:ite1 buff1 p9k br[n1 gray4 ,x resembles "s lime/one1 & ^! two rocks actually are closely relat$4 ,to help tell !m ap>t1 dilute hydro*loric acid (t5 is us$4 ,a few drops ( ?is acid w readily fizz & bubble if ! rock y put !m on is a lime/one4 ,if ! rock is dolomite1 ! acid w eff]vesce only v little or n at all4 7,if1 h[ev]1 ! acid is put on p[d]$ dolomite1 x !n w fizz readily47 ,dolomite is slightly h>d] ?an lime/one1 & x also is slightly heavi]4 ,"s dolomite rocks =m$ directly f mat]ials t 7 dissolv$ 9 sea wat]1 & o!rs are alt]$ lime/one rocks4 ,"s lime/ones alt]$ into dolomite on ! sea floor by ! addition ( magnesium f ! sea wat]4 ,o!rs *ang$ into dolomite mu* lat] aft] ! sea _h )drawn & ! lime/ones _h become a "p ( ! l&2 und]gr\nd wat]s conta9+ magnesium seep$ ?r\gh ^! lime/ones & alt]$ !m into dolomite4 ,_m ( ! dolomite rocks are f\nd ) lime/ones4 ,9 ,texas !y occur mo/ly 9 ,cambrian1 ,ordovician1 ,mississippian1 ,p5nsylvanian1 ,p]mian1 & ,cretace\s =mations4 ,! geologic map 7pp4 #d-e7 indicates :]e ^! /rata appe> at ! surface 9 ,texas4 ,dolomite is abundant 9 ! ,llano uplift area ( c5tral ,texas--p>ticul>ly 9 ! ,cambrian & ,ordovician rocks4 ,a numb] ( ^! c5tral ,texas dolomites h be5 qu>ri$ = use z build+ /ones4 ,"s ( !m also h be5 cru%$ & us$ z a road-build+ mat]ial & z a /one aggregate t is mix$ ) cem5t to make concrete4 ,?is dolomite is also us$ z t]razzo *ips 7t]razzo floors are describ$ ) s]p5t9e on p4 #hh74 ,9 addition1 ,ell5burg] 7,ordovician7 dolomite f ,burnet ,c\nty 0 us$ dur+ ,_w ,w> ,,ii z a s\rce ( ! lightweight metal magnesium4 ,dravite4 ,see ,t\rmal9e4 ,feldsp> ,feldsp> is ! "n giv5 to a gr\p ( nonmetallic m9]als t are mu* alike4 ,sev]al ( !m are s simil> t a petrographic microscope mu/ be us$ to tell !m ap>t4 ,ea* ( ! feldsp> m9]als is an alum9um silicate4 ,ea* ( !m conta9s1 9 addition1 at lea/ "o ( ! foll[+ elem5ts3 potassium1 sodium1 calcium1 & b>ium4 ,! feldsp> m9]als t are f\nd 9 ,texas include albite1 a sodium-alum9um silicate1 & or?oclase & microcl9e1 :i* are bo? potassium-alum9um silicates4 ,! feldsp> m9]als are transp>5t to transluc5t & h ei!r glassy or pe>ly lu/]s4 ,!y c be :ite1 cream1 or a %ade ( r$1 br[n1 yell[1 blue1 gray1 or gre54 ,:5 y rub a feldsp> across a /reak plate1 x leaves a :ite /reak4 ,! feldsp>s are r h>d--a pocket knife w n scrat* !m1 al?\gh a piece ( qu>tz or a /eel file w4 ,^! m9]als h good cleavage 9 two directions4 ,! cleavages meet at an angle ( ab\t #ij1 s t ! cleavage fragm5ts h squ>e corn]s4 ,illu/ration3 ,feldsp> cleavage fragm5t f ,llano ,c\nty1 ,texas4 ,! two directions ( good cleavage meet at an angle ( ab\t #ij4 ,! feldsp>s are important rock-=m+ m9]als4 ,y c f9d !m 9 igne\s rocks1 su* z granite or pegmatite1 & 9 metamorphic rocks1 su* z gneiss4 ,!y also occur z fragm5ts 9 s$im5t>y rocks1 su* z "s s&/one & conglom]ate4 ,al?\gh ! feldsp>s c orig9ate 9 o!r ways1 !y =m mo/ly f hot magmas t cool & cry/allize into igne\s rocks4 ,^! m9]als occur 9 ! rocks z gra9s1 z cleavable masses1 & z individual cry/als4 ,! cry/als may be %ap$ l prisms1 or !y may be flat & slabby4 ,good places to look = feldsp>s are 9 areas :]e granites1 pegmatites1 & o!r intrusive igne\s rocks appe> at ! surface4 ,! pegmatite rocks ( ,burnet1 ,gillespie1 ,llano1 & ,mason c\nties 9 ! ,llano uplift area ( c5tral ,texas1 & ^? ( ! ,van ,horn ,m\nta9s 9 ,hudspe? & ,culb]son c\nties 9 we/ ,texas1 are especially good s\rces ( feldsp>4 ,l>ge cleavable masses & cry/als t are m ?an a foot long are f\nd 9 "s ( ^! rocks4 ,! feldsp>s h a numb] ( uses4 ,"s ( ! pegmatite feldsp>s f ,llano ,c\nty 9 c5tral ,texas h be5 cru%$ & us$ z granules = built-up & composition ro(s4 ,9 addition1 "s h be5 %ipp$ to ,mexico = glass-mak+4 ,"s ( ! o!r uses ( feldsp> are 9 mak+ porcela91 c]amic glazes1 & sc\r+ comp\nds4 ,a few ( ! feldsp> m9]als1 su* z ! v>iety ( microcl9e kn[n z amazon/one1 are us$ z gem/ones4 ,illu/ration3 ,microcl9e feldsp> cry/als f ne> ,granite ,%oals ,lake1 ,llano ,c\nty1 ,texas4 ,fibr\s ,gypsum4 ,see ,gypsum4 ,fl9t4 ,see ,qu>tz4 ,fluorite ,fluorite is calcium fluoride4 ,! fluorite t is m9$ & s5t to m>ket1 h[ev]1 commonly is f\nd mix$ ) qu>tz1 calcite1 lime/one1 or o!r rocks & m9]als4 ,indu/ry calls ?is mixture fluorsp>4 ,fluorite is a transp>5t to transluc5t m9]al t has a glassy lu/]4 ,x may be colorless1 or x may be :ite1 p9k1 gre51 purple1 br[n1 or blue4 ,"s specim5s %[ m ?an "o color4 ,:5 y rub fluorite across a /reak plate1 x leaves a :ite /reak4 ,?is m9]al is n p>ticul>ly h>d--a pocket knife w scrat* x1 al?\gh a copp] p5ny w n4 ,fluorite has p]fect cleavage 9 f\r directions4 ,by c>efully break+ a specim51 y c obta9 cleavage fragm5ts t are %ap$ l octah$rons4 ,fluorite occurs z cleavable masses1 z f9e or co>se gra9s1 & z cry/als4 ,mo/ ( ! cry/als are cubes1 b "s may be octah$rons1 dodecah$rons1 or comb9ations ( ^!4 ,fluorite has be5 f\nd bo? 9 we/ ,texas & 9 c5tral ,texas4 ,9 ! ,llano uplift area ( c5tral ,texas1 x occurs 9 a numb] ( ,precambrian granite1 pegmatite1 s*i/1 & gneiss rocks4 ,! mo/ important1 al?\gh small1 deposit 9 ?is area is ne> ,spr+ ,creek a few miles we/ ( ,burnet 9 ,burnet ,c\nty4 ,"h1 prospectors h dug holes & pits 9 gneiss & s*i/ rocks & f\nd lay]s ( fluorite 9 !m4 ,! l>ge/ kn[n fluorite deposits 9 ,texas 7!y are n p>ticul>ly l>ge :5 y comp>e !m ) ! deposits 9 ,ill9ois & ,k5tucky7 are ^? 9 ! ,eagle ,m\nta9s ( ,hudspe? ,c\nty4 ,?is fluorite occurs 9 bo? igne\s & s$im5t>y rocks4 ,_m ye>s ago1 probably dur+ ! late "p ( ! ,t]ti>y ,p]iod1 hot magma f> bel[ ! surface gave (f liquids & gases conta9+ fluor9e4 ,^! fluids mov$ up ?r\gh l>ge cracks 7call$ faults7 9 ,cretace\s lime/ones & ,t]ti>y igne\s rocks & deposit$ fluorite 9 !m4 ,9 places1 b$s ( lime/one h be5 replac$ by fluorite4 ,"s ( ?is we/ ,texas fluorite has be5 m9$ & %ipp$ to m>ket4 ,illu/ration3 ,fluorite has octah$ral cleavage4 ,! f\r directions ( p]fect cleavage c result 9 cleavage fragm5ts t are octah$rons4 ,fluorite is extremely important z a flux 9 /eel-mak+ to help ! +r$i5ts ( ! molt5 /eel bl5d toge!r4 ,9 addition1 x comb9es ) sulfur1 phosphorus1 & o!r unwant$ sub/ances s t !y c be remov$ f ! /eel4 ,o!r important uses ( fluorite are 9 glass-mak+ & 9 ! manufacture ( hydr(luoric acid4 ,?is acid is us$ 9 ! alum9um indu/ry z well z 9 indu/ries t make high-octane gasol9e1 insecticides1 & refrig]ants = refrig]ators & freez]s4 ,gal5a ,gal5a1 lead sulfide1 is a %9y1 lead-gray1 metallic m9]al t has a specific gravity ( #g4d to #g4f4 ,x is s(t en\gh to m>k pap]1 & x leaves a grayi%-black /reak on a /reak plate4 ,?is m9]al cleaves p]fectly 9 ?ree directions1 & ! cleavage fragm5ts h squ>e corn]s--"s are cubes4 ,gal5a occurs z cleavable masses1 z f9e or co>se gra9s1 & z cry/als1 mo/ ( :i* are cubes4 ,gal5a commonly is associat$ ) o!r m9]als2 = example1 "s ( ! we/ ,texas gal5a ei!r conta9s "s silv] 7!n call$ arg5tif]\s gal5a7 or occurs ) x4 ,sphal]ite1 a z9c m9]al1 is commonly f\nd ) gal5a4 ,gal5a is an important m9]al because x is ! *ief s\rce ( lead4 ,comp\nds ( lead1 call$ :ite lead1 r$ lead1 & li?>ge1 are us$ z pa9t pigm5ts4 ,automobile batt]ies conta9 lead plates1 & tetrae?yl lead is add$ to gasol9e to keep ! c>'s motor f knock+4 ,"s o!r uses ( lead are 9 bullets1 type metal1 sold]1 & cable cov]+s4 ,illu/ration3 ,gal5a has p]fect cubic cleavage4 ,! ?ree directions ( cleavage are at "r angles to ea* o!r result+ 9 cubic cleavage fragm5ts4 ,gal5a has be5 f\nd 9 sev]al areas ( ,texas & has be5 m9$ 9 c5tral & we/ ,texas4 ,none1 h[ev]1 has be5 produc$ 9 rec5t ye>s4 ,mo/ ( ! gal5a m9$ 9 we/ ,texas 0 obta9$ f silv] m9es1 :]e ! gal5a 0 a by-product4 ,"s ( ! we/ ,texas gal5a deposits are at ,altuda ,m\nta9 ea/ ( ,alp9e 9 ,brew/] ,c\nty1 9 ! ,eagle ,m\nta9s & ! ,quitman ,m\nta9s 9 ,hudspe? ,c\nty1 & 9 ! ,*9ati ,m\nta9s & ! ,%aft] area 9 ,presidio ,c\nty4 ,mo/ ( ! m9+ has be5 f ! ,%aft] area 7?is area is describ$ ) silv] m9]als on p4 #ij74 ,9 c5tral ,texas1 sev]al small gal5a deposits h be5 f\nd 9 ,blanco1 ,burnet1 & o!r c\nties ( ! ,llano uplift area4 ,"s gal5a has be5 m9$ at ,silv] ,creek 9 nor?we/]n ,burnet ,c\nty4 ,"h1 gal5a occurs 9 cracks & z scatt]$ gra9s 9 ,cambrian lime/ones & s&/ones4 ,x is probable t mu* ( ! gal5a 9 we/ ,texas & 9 c5tral ,texas 0 =m$ :5 hot magma =c$ out solutions conta9+ lead4 ,^! solutions mov$ up ?r\gh cracks & o!r op5+s 9 ! subsurface rocks & deposit$ ! gal5a 9 !m4 ,small am\nts ( gal5a1 :i* likely _h a diff]5t orig91 h be5 f\nd 9 ,fi%]1 ,fo>d1 ,h>deman1 & ,"y c\nties4 ,a little occurs also 9 rocks associat$ ) salt 9 a numb] ( ! ,gulf ,coa/al ,pla9 salt domes4 ,g>net ,g>net is n "o m9]al b is ! "n giv5 to a gr\p ( sev]al m9]als t are v mu* alike4 ,9 fact1 x (t5 is impossible to tell "s ( !m ap>t )\t us+ special laboratory te/s4 ,illu/ration3 ,g>net cry/al =ms include3 ,a1 trapezoh$ron2 ,b1 dodecah$ron2 ,c & ,d1 comb9ation trapezoh$ron & dodecah$ron4 ,! g>net m9]als h glassy to res9\s lu/]s & are transp>5t or transluc5t4 ,a pocket knife w n scrat* !m1 & "s specim5s are too h>d ev5 = qu>tz to scrat*4 ,two ( ! g>net m9]als mo/ commonly f\nd 9 ,texas are alm&ite1 an iron-alum9um silicate1 & grossul>ite1 a calcium-alum9ium silicate4 ,alm&ite has a deep-r$ or a br[ni%-r$ color4 ,grossul>ite is pale gre51 br[ni% yell[1 c9namon br[n1 or rose r$4 ,g>net m9]als occur z cry/als & z masses t are scatt]$ ?r\gh "s ( ! metamorphic & igne\s rocks4 ,aft] !y h wea!r$ out ( ^! rocks1 ! g>nets make up a "p ( _m s&s & s&/ones4 ,because ^! m9]als s commonly occur z cry/als1 x is helpful to le>n to recognize ! cry/al %apes4 ,g>net m9]als are f\nd 9 ! igne\s & metamorphic rocks ( bo? c5tral ,texas & we/ ,texas4 ,9 c5tral ,texas1 !y occur 9 anci5t ,precambrian s*i/ & pegmatite rocks ( ! ,llano uplift area4 ,"s ( ^! c5tral ,texas g>net localities are 9 nor!a/]n ,mason ,c\nty1 c5tral & nor?we/]n ,llano ,c\nty1 we/-c5tral ,burnet ,c\nty1 & nor!a/]n ,gillespie ,c\nty4 ,9 we/ ,texas1 g>nets occur 9 metamorphic rocks 9 ! ,quitman ,m\nta9s1 :i* are s\?we/ ( ,si]ra ,blanca 9 ,hudspe? ,c\nty1 & 9 ! ,mica ,m9e area1 :i* is s\? ( ,van ,horn ne> ! ,hudspe?-,culb]son ,c\nty l9e4 ,g>nets also h be5 f\nd 9 igne\s rocks 9 ! ,frankl9 ,m\nta9s a few miles nor? ( ,el ,paso 9 ,el ,paso ,c\nty4 ,g>nets t are f\nd 9 metamorphic rocks su* z s*i/s 7 =m$ :5 great =ces squeez$ & heat$ rocks f> bel[ ! e>?'s surface4 ,?is heat & pressure caus$ elem5ts 9 ! rocks to jo9 toge!r into diff]5t comb9ations to =m new m9]als1 su* z g>nets4 ,g>nets t occur scatt]$ ?r\gh igne\s rocks1 su* z "s pegmatites & granites1 cool$ & cry/alliz$ f hot1 igne\s fluids :5 ! rocks !mselves =m$4 ,mo/ ,texas g>nets are n transp>5t4 ,a few1 h[ev]1 are cle> en\gh to be us$ z gem/ones4 ,^! c be cut1 poli%$1 & m\nt$ 9 r+s1 broo*es1 bracelets1 & e>r+s4 ,al?\gh "s g>net is widely us$ z an abrasive1 none f ,texas has be5 produc$ = ?is purpose4 ,gneiss ,gneiss is a metamorphic rock t has p>allel lay]s or b&s4 ,"s gneiss is made up ( ! same m9]als 7*iefly feldsp> & qu>tz7 z granite1 & x is !n call$ granite gneiss4 ,sev]al ( ! o!r k9ds ( gneiss are kn[n z mica gneiss1 conglom]ate gneiss1 gabbro gneiss1 & hornbl5de gneiss4 ,9 ord] to be a gneiss1 a metamorphic rock has to h b&s or lay]s4 ,^! b&s may be ei!r /raight or wavy & ei!r wide or n>r[4 ,9 mo/ gneisses1 y w f9d a lay] made up ( long or flat m9]al gra9s next to a lay] made up ( ! gra9s ( an entirely diff]5t m9]al4 ,! b&s may %[ color diff]5ces1 too4 ,= example1 a p9k lay] made up ( feldsp> gra9s may be f\nd next to a black lay] made up ( hornbl5de gra9s4 ,! m9]al gra9s int]lock z !y d 9 igne\s rocks1 & !y are g5]ally l>ge en\gh to be se5 )\t a magnify+ glass4 ,illu/ration3 ,gneiss f ,blanco ,c\nty1 ,texas1 %[+ light & d>k b&s4 ,gneiss c =m f an igne\s rock1 su* z granite1 or f a s$im5t>y rock1 su* z s&/one4 ,heat1 fluids1 & pressures bel[ ! e>?'s surface *ange ^! rocks into gneiss4 ,gneiss t =m$ dur+ ,precambrian "t is n[ se5 at ! surface 9 bo? we/ ,texas & c5tral ,texas4 ,9 we/ ,texas1 x occurs pr9cipally 9 ! ,van ,horn area ( ,culb]son & ,hudspe? c\nties4 ,9 c5tral ,texas1 x is f\nd 9 ,blanco1 ,burnet1 ,gillespie1 ,llano1 & ,mason c\nties ( ! ,llano uplift area4 ,"o ( ! ,llano uplift rocks is call$ ! ,valley ,spr+ ,gneiss4 ,x g5]ally has a light color 7mu* ( x is p9ki%71 & x is believ$ to h once be5 a s&/one4 ,ano!r gneiss ( ?is area1 ! ,big ,bran* ,gneiss1 :i* has a m$ium to d>k gray color1 occurs 9 nor!rn ,gillespie & ,blanco c\nties & is an alt]$ igne\s rock4 ,"s ( ! ,texas gneiss rocks are suitable = use z build+ /ones4 ,gold ,gold commonly occurs 9 nature z a s+le elem5t--gold--b mu* native gold has a small am\nt ( "s o!r elem5t1 su* z silv]1 copp]1 or iron1 mix$ ) x4 ,native gold is a %9y1 yell[1 metallic m9]al t does n t>ni%1 & x leaves a %9y1 gold5-yell[ /reak :5 y rub x across a /reak plate4 ,if silv] is pres5t1 ! color & /reak h a light] %ade4 ,pure gold is extremely heavy--its specific gravity is #ai4c4 ,because x is malleable1 ?is m9]al w flatt5 into a ?9 %eet :5 hamm]$4 ,x is ductile en\gh to be drawn out into wires4 ,gold is also s(t--a pocket knife w scrat* x easily4 ,:5 x is to be us$ = ornam5ts & jewelry1 gold is usually mix$ ) o!r metal1 su* z silv]1 copp]1 nickel1 or palladium1 to make x h>d]4 ,! am\nt ( gold t is pres5t is !n indicat$ by c>ats 7or k>ats74 ,pure gold is #bd c>ats4 ,if y h a gold r+ t has #ad ,k /amp$ inside x1 y "k t x is made ( a mixture ( #ad p>ts gold & #aj p>ts ( o!r metal4 ,gold commonly occurs 9 nature z plates1 scales1 or gra9s4 ,"s ( ! gra9s are l>ge en\gh to be call$ nuggets4 ,x also is f\nd 9 a wire-l %ape describ$ z fili=m1 x occurs 9 a network1 call$ reticulate1 & x c h a bran*+ & f]n-l %ape1 describ$ z d5dritic4 ,gold is n (t5 f\nd z individual cry/als4 ,sev]al o!r m9]als1 su* z pyrite1 *alcopyrite1 & mica1 are sometimes mi/ak5 = gold4 ,none ( ^!1 h[ev]1 is malleable & ductile1 & none is ne>ly z heavy z gold4 ,pyrite & *alcopyrite h d>k-color$ /reaks unlike t ( gold4 ,mica cleaves s p]fectly t x c be split into ?91 flat %eets1 b gold has no cleavage at all4 ,! be/ places to look = gold are 9 areas ne> igne\s rocks & along ! creeks & riv]s t dra9 ^! areas4 ,x is ?\ght t mo/ gold orig9ally 0 c>ri$ up f molt5 igne\s rock by hot solutions4 ,! solutions mov$ into cracks & o!r op5+s 9 ne>by rocks & deposit$ ! gold1 commonly along ) qu>tz4 ,lat]1 "s ( ^! gold-be>+ rocks wea!r$ away4 ,! gold t ! rocks conta9$ ei!r rema9$ at ! spot or 0 wa%$ into creeks & riv]s4 ,^! transport$ accumulations ( loose gold are call$ plac] deposits4 ,illu/ration3 ,plac] gold 9 v small quantities has be5 f\nd 9 "s ( ! /ream gravels ( ,texas4 ,no really important gold deposit has ev] be5 f\nd 9 ,texas1 al?\gh traces & small am\nts h be5 report$ 9 sev]al areas4 ,a little gold has be5 f\nd 9 ! ,llano uplift area ( c5tral ,texas4 ,x occurs 9 qu>tz ve9lets t cut ?r\gh "s ( ! ,precambrian metamorphic rocks ( ,llano1 ,mason1 nor!a/]n ,gillespie1 & we/-c5tral ,burnet c\nties4 ,_m ye>s ago1 a small am\nt ( gold 0 m9$ nor!a/ ( ,llano 9 ,llano ,c\nty f ! ,hea? m9e4 ,"s gold also has be5 f\nd 9 s&s & gravels along /reams1 su* z along ,s&y ,creek & its tribut>ies1 9 p>ts ( ?is ,llano uplift area4 ,9 ! ,trans-,pecos c\ntry ( we/ ,texas1 small am\nts ( gold h be5 f\nd 9 ! ,van ,horn area ( ,culb]son & ,hudspe? c\nties1 9 ! ,quitman ,m\nta9s di/rict ( ,hudspe? ,c\nty1 & 9 ! c\ntry ar\nd ,%aft] 9 ,presidio ,c\nty4 ,mo/ ( ! small quantity ( gold t 0 m9$ 9 we/ ,texas 0 obta9$ z a by-product f ! ,presidio m9e 9 ! ,%aft] di/rict 7describ$ ) silv] m9]als on p4 #ij74 ,small am\nts ( gold h be5 report$ f o!r p>ts ( ,texas4 ,"s ( ^! localities are 9 ,eoc5e ,t]ti>y s&/ones 9 ! ,gulf ,coa/al ,pla91 9 ,cretace\s lime/ones 9 ,irion1 ,uvalde1 & ,williamson c\nties1 & 9 s& & gravel 9 ,h[>d & ,taylor c\nties4 ,none ( ^! deposits has be5 f\nd to h any comm]cial value4 ,granite ,granite is an intrusive igne\s rock t is made up *iefly ( cry/all9e gra9s or cry/als ( qu>tz & a feldsp> m9]al1 su* z or?oclase or microcl9e4 ,sev]al o!r m9]als1 includ+ mica & hornbl5de1 may also be pres5t4 ,all ( ! m9]al gra9s 9 granite are ab\t ! same size1 & y c di/+ui% !m )\t us+ a magnify+ glass4 ,a granite may be co>se gra9$1 m$ium gra9$1 or f9e gra9$4 ,:5 y exam9e ?is rock1 y w see t its gra9s are n cem5t$ b int]lock$ l ! pieces ( a jigsaw puzzle4 ,! color ( granite1 :i* is p9k1 r$1 gray1 or br[ni%1 dep5ds *iefly on ! color ( its feldsp> gra9s4 ,mo/ granites =m$ f hot1 molt5 magma t sl[ly cool$ & h>d5$ f> bel[ ! e>?'s surface4 ,because ( ?is sl[ cool+1 fairly l>ge m9]al gra9s 7 =m$4 ,illu/ration3 ,poli%$ section ( p9k granite f ,gillespie ,c\nty1 ,texas4 ,granites are n[ se5 at ! surface 9 sev]al areas ( ,texas4 ,!y 7 gradually uncov]$ z ! areas became high] & ! ov]ly+ rocks sl[ly wea!r$ away4 ,"o ( ^! areas is ! ,llano uplift ( c5tral ,texas :]e ! granites occur 9 ,blanco1 ,burnet1 ,gillespie1 ,llano1 & ,mason c\nties4 ,^! granites =m$ dur+ ,precambrian "t & are believ$ to be ab\t a billion ye>s old4 7,sci5ti/s are n[ able to det]m9e ! age ( "s rocks accurately by v precisely measur+ ! relative am\nts ( isotopes produc$ by decay ( radioactive m9]als47 ,illu/ration3 ,texas ,/ate ,capitol build+ at ,au/9 is made ( ,burnet ,c\nty granite obta9$ f ,granite ,m\nta9 ne> ,m>ble ,falls1 ,texas4 ,granites also appe> at ! surface 9 ! ,trans-,pecos c\ntry ( we/ ,texas4 ,"s ( ^! areas include ! ,frankl9 ,m\nta9s ( ,el ,paso ,c\nty1 ! ,quitman ,m\nta9s ( ,hudspe? ,c\nty1 ! ,*isos ,m\nta9s ( ,brew/] ,c\nty1 & ! ,*9ati ,m\nta9s ( ,presidio ,c\nty4 ,r$1 p9k1 & gray granites f qu>ries 9 ! ,llano uplift area are widely us$ z build+ /ones & monum5t /ones4 ,a l>ge qu>ry at ,granite ,m\nta9 j we/ ( ,m>ble ,falls 9 ,burnet ,c\nty has suppli$ p9k granite = build+s 9 _m p>ts ( ! ,unit$ ,/ates4 ,! ,texas ,capitol build+ & sev]al o!r ,/ate build+s 9 ,au/9 are made ( ?is granite4 ,graphite ,graphite is a m9]al t is made up ( a s+le elem5t--c>bon4 7,diamond1 al?\gh x does n look at all l graphite1 is a cry/all9e =m ( c>bon47 ,graphite is a /eel-gray or black m9]al t commonly has a metallic lu/]4 ,x is n heavy & is extremely s(t4 ,graphite w soil y\r f+]s & leave a black m>k on pap]4 ,?is m9]al cleaves p]fectly 9 "o direction & splits into ?9 flakes t feel greasy4 ,to help di/+ui% graphite f molybd5ite1 a m9]al x resembles1 y c use a %9y1 glaz$ surface1 su* z is f\nd on a sauc] or a plate1 to te/ its /reak4 ,:5 rubb$ across ?is k9d ( surface1 graphite w leave a black /reak1 b molybd5ite w leave a gre5i% "o4 ,graphite commonly occurs z scales1 z %eet-l lay]s1 or z compact masses4 ,x may be f\nd mix$ ) clay or o!r impurities1 & x !n looks dull & e>?y4 ,cry/als ( graphite1 :i* are seldom f\nd1 are #f-sid$ & flat4 ,graphite occurs 9 ,llano1 ,burnet1 & o!r c\nties 9 ! ,llano uplift area ( c5tral ,texas4 ,"o ( ! ,nation's mo/ important graphite m9es is locat$ 9 ! ,cle> ,creek area sev]al miles nor?we/ ( ,burnet 9 ,burnet ,c\nty4 ,"s graphite has also be5 m9$ ne> ,lone ,grove 9 ,llano ,c\nty4 ,9 addition1 a graphite s*i/1 obta9$ s\? ( ,llano 9 ,llano ,c\nty1 has be5 us$ z a filt]+ mat]ial4 ,illu/ration3 ,graphite is us$ 9 p5cil lead1 g5]ator bru%es1 & lubricants4 ,all ( ?is graphite occurs 9 extremely old ,precambrian graphite s*i/ rocks t we n[ see at ! surface 9 ?is "p ( ,texas4 ,x is believ$ t ! s*i/s 7 once anci5t s$im5t>y rocks1 su* z %ales1 :i* conta9$ organic matt]4 ,long ago1 great =ces bel[ ! e>?'s surface alt]$ ^! rocks4 ,:5 ?is happ5$1 ! organic mat]ial t !y conta9$ *ang$ into ! m9]al we "k z graphite4 ,graphite has a numb] ( uses4 ,x is mix$ ) clay to make ! p5cil lead t we use = writ+4 ,x s]ves z a lubricant1 ei!r alone or mix$ ) oil1 grease1 or wat]4 ,9 addition1 graphite is us$ to make g5]ator bru%es1 /ove & %oe poli%1 & special pa9ts4 ,because x c /& great heat )\t melt+1 "s graphite is mix$ ) clay to make ! pots or crucibles t hold molt5 metals4 ,grossul>ite4 ,see ,g>net4 ,gypsite4 ,see ,gypsum4 ,gypsum ,gypsum is a hydr\s calcium sulfate4 ,?is m9]al is normally colorless or :ite1 b impurities cause x to appe> gray1 br[ni%1 yell[i%1 or r$di%4 ,x is transp>5t or transluc5t & is n heavy4 ,:5 y rub gypsum across a /reak plate1 x leaves a :ite /reak4 ,?is m9]al is s s(t t a f+]nail scrat*es x easily4 ,gypsum occurs 9 sev]al v>ieties4 ,! colorless1 glassy1 & transp>5t v>iety ( gypsum is call$ sel5ite4 ,x is f\nd z cleavable masses & z cry/als t are prism-%ap$ or flat & diamond-%ap$4 ,x is n uncommon = two cry/als to be jo9$ toge!r s t !y h a swall[-tail %ape--^! cry/als are tw9n$4 ,gr\ps ( flat sel5ite cry/als arrang$ toge!r s t !y resemble fl[]s are call$ rosettes4 ,_m ( ^! h be5 f\nd 9 ,nolan ,c\nty4 ,gypsum has f\r directions ( cleavage4 ,"o ( ^! directions is s p]fect t "s sel5ite splits into ?91 cle> %eets t may be mi/ak5 = mica2 o!r sel5ite cleavage fragm5ts may be mi/ak5 = calcite4 ,y c di/+ui% sel5ite %eets f calcite by te/+ _! h>dness 7sel5ite is s(t]7 & by putt+ a drop or two ( dilute hydro*loric acid on !m4 ,! acid w fizz & bubble on calcite b n on ! sel5ite gypsum4 ,!re is also a quick way to di/+ui% ! ?9 sel5ite cleavage fragm5ts f mica4 ,aft] y c>efully b5d a ?9 %eet ( mica1 x w snap back to its orig9al %ape )\t break+4 ,sel5ite gypsum1 h[ev]1 is n ela/ic4 ,x w b5d1 b x w break if y try to /raight5 x aga94 ,illu/ration3 ,sel5ite gypsum cry/al f ,ba/rop ,c\nty1 ,texas4 ,sel5ite is f\nd 9 cracks & cavities 9 rocks4 ,good cry/als h be5 collect$ at ,gyp ,hill1 a salt dome s\!a/ ( ,falfurrias 9 ,brooks ,c\nty1 & "s sel5ite has be5 m9$ !re4 ,sel5ite cry/als also occur scatt]$ ?r\gh clays1 p>ticul>ly along creek banks1 9 ,lee1 ,fayette1 ,ba/rop1 & sev]al o!r c\nties4 ,ano!r v>iety ( gypsum is kn[n z fibr\s gypsum4 ,x is made up ( sl5d]1 brittle1 ne$le-l fib]s t fill ! cracks 9 "s rocks4 ,if fibr\s gypsum has a silky or pe>ly lu/]1 x is call$ sat9 sp>4 ,"o ( ! places :]e sat9 sp> occurs is 9 ,p]mian rocks 9 ,h>deman ,c\nty4 ,illu/ration3 ,sel5ite gypsum rosettes f ,nolan ,c\nty1 ,texas4 ,mo/ ( ! fibr\s gypsum & sel5ite is =m$ by solutions4 ,"s ( ^! solutions develop :5 und]gr\nd wat]s1 seep+ ?r\gh rocks1 pick up & dissolve m9]als t conta9 sulfur 7su* z pyrite74 ,?is dissolv$ mat]ial *anges ! wat] into v weak sulfuric acid4 ,:5 ! sulfuric acid meets calcium c>bonate 7z 9 lime/one or calcite71 x comb9es ) ! calcium to =m ! gypsum4 ,illu/ration3 ,fibr\s gypsum f ,t]l+ua area1 ,brew/] ,c\nty1 ,texas4 ,a massive1 f9e-gra9$1 & transluc5t v>iety ( gypsum1 kn[n z alaba/]1 is us$ = articles su* z lamp bases1 /atuettes1 vases1 & book-ends4 ,a loose1 e>?y1 crumbly v>iety ( gypsum1 call$ gypsite1 is ord9>ily f\nd mix$ ) o!r mat]ials1 su* z clay1 s&1 & soil4 ,x occurs ei!r at or ne> ! surface ( ! gr\nd4 ,gypsite is f\nd 9 ,culb]son1 ,reeves1 & o!r c\nties 9 we/ ,texas4 ,a massive1 granul> v>iety ( gypsum1 call$ rock gypsum1 may occur 9 l>ge deposits4 ,?is is ! gypsum t is us$ = mak+ products su* z pla/]1 wallbo>d1 & "s cem5ts4 ,deposits ( rock gypsum are f\nd bo? und]gr\nd & at ! surface 9 ,texas4 ,surface deposits occur 9 ,p]mian rocks 9 sev]al c\nties to ! ea/ ( ! ,texas ,high ,pla9s4 ,!y also occur 9 ! area betwe5 ! ,pecos ,riv] & ! ,delaw>e & ,apa*e ,m\nta9s 9 ,culb]son & ,reeves c\nties4 ,"s ( ! o!r surface deposits are f\nd ne> ! ,malone ,m\nta9s 9 ,hudspe? ,c\nty & 9 ,l[] ,cretace\s rocks 9 ,gillespie & ,m5>d c\nties4 ,rock gypsum has be5 m9$ f ! deposits 9 ,fi%]1 ,gillespie1 ,h>deman1 ,hudspe?1 & ,nolan c\nties4 ,x also has be5 produc$ f ! cap-rock at ,hockley salt dome 9 ,h>ris ,c\nty4 ,gypsum & ano!r m9]al1 anhydrite1 h v ne>ly ! same composition4 ,bo? are calcium sulfates4 ,gypsum1 h[ev]1 conta9s wat] ( cry/allization1 & anhydrite does n4 ,x is likely t mo/ ( ! rock-gypsum deposits ( ,texas orig9ally 7 b$s ( anhydrite4 ,by absorb+ wat] t seep$ ?r\gh x1 ! anhydrite *ang$ into gypsum4 ,halite ,halite1 sodium *loride1 is ! table salt y spr9kle on food = season+4 ,?is m9]al ord9>ily is :ite or colorless1 b o!r mat]ials cause x to be t9t$ r$1 blue1 gray1 br[n1 or gre54 ,:5 y rub halite across a /reak plate1 x leaves a :ite /reak4 ,because halite cleaves 9 ?ree directions1 all at "r angles to ea* o!r1 ! cleavage fragm5ts are %ap$ l cubes4 ,y c see "s ( !m by look+ at a few gra9s ( table salt ?r\gh a magnify+ glass4 ,halite has a salty ta/e & dissolves easily 9 wat]4 ,x also is transp>5t to transluc5t & has a glassy lu/]4 ,?is m9]al is s(t en\gh = a copp] p5ny to scrat* x4 ,halite commonly occurs z cubic cry/als & z granul> or compact masses4 ,9 addition to its use z table salt1 mu* halite goes to make soda a%1 *lor9e1 & o!r *emicals4 ,a few ( its o!r uses are 9 lea!r mak+1 meat pack+1 & food cann+4 ,texas has l>ge und]gr\nd deposits ( halite4 ,^! deposits1 kn[n z rock salt1 occur 9 ! ,p]mian subsurface bas9 ( we/ ,texas & 9 ! salt domes ( ! ,gulf ,coa/al ,pla94 ,! ,p]mian bas91 :i* ext5ds "u p>ts ( we/ ,texas1 ,new ,mexico1 ,oklahoma1 ,colorado1 & ,kansas1 is n[ completely fill$ ) s$im5ts4 ,x appe>s level & flat :5 y travel across x & does n look at all l a bas9 or a valley4 ,dur+ ,p]mian "t1 h[ev]1 ?is area 0 cov]$ by a salty sea4 ,z ! sea gradually dri$ up1 ! dissolv$ mat]ial t x conta9$ 0 deposit$ z ?ick b$s ( halite1 anhydrite1 & o!r m9]als4 ,lat]1 ^! m9]als 7 cov]$ by s$im5t>y rocks :i* 7 deposit$ on top ( !m4 ,n[1 ! m9]als are f\nd _m hundr$s ( feet bel[ ! surface4 ,9 ,hut*9son1 ,mit*ell1 ,w>d1 & ,yoakum c\nties1 "s ( ?is ,p]mian bas9 salt has be5 produc$ 7z br9e7 f wells t h be5 drill$ into x4 ,illu/ration3 ,salt domes1 :i* are huge1 und]gr\nd columns ( halite1 occur on ! ,gulf ,coa/al ,pla94 ,! ,gulf ,coa/al ,pla9 salt domes are huge & almo/ circul> columns ( halite1 "s ( :i* are m ?an #b miles wide4 ,"s are less ?an #cjj feet bel[ ! surface1 b mo/ ( !m are mu* deep]4 ,^! salt columns pu%$ upw>d _m ?\s&s ( feet f great1 deeply buri$ salt deposits4 ,! halite is m9$ f %afts dug into ! ,hockley salt dome 9 ,h>ris ,c\nty & into ! ,gr& ,sal9e salt dome 9 ,van ,z&t ,c\nty4 ,salt br9es are produc$ f wells drill$ into sev]al salt domes ( ?is area4 ,at ! surface 9 ,texas1 halite occurs 9 salt lakes 9 ,crane & ,hudspe? c\nties & 9 alkali lakes on ! ,high ,pla9s4 ,x is f\nd also on ! %ores ( bays & lagoons 9 ,cam]on1 ,k5$y1 ,kleb]g1 & ,willacy c\nties1 & x occurs at spr+s & seepages 9 v>i\s places 9 ! ,/ate4 ,hematite ,hematite1 iron oxide1 ! *ief ore ( iron1 is f\nd 9 _m places 9 ,texas b n 9 l>ge deposits4 ,?is m9]al may h a metallic lu/] & appe> r$di% br[n1 d>k br[n1 /eel gray1 or black or x may occur z a s(t1 r$1 e>?-l mat]ial call$ r$ o*]4 ,illu/ration3 ,specul> hematite f ,c>rizo ,m\nta9s1 ,hudspe? ,c\nty1 ,texas4 ,mo/ metallic hematite is too h>d = a pocket knife to scrat*1 b qu>tz or a /eel file w scrat* x4 ,hematite is fairly heavy1 = x has a specific gravity ( #e4bf4 ,?is m9]al has no cleavage1 b "s specim5s %[ ?ree directions ( p>t+ t are almo/ at "r angles to ea* o!r4 ,a great help 9 id5tify+ hematite is ! d>k r$di%-br[n /reak x leaves :5 y rub x across a /reak plate4 ,"s hematite occurs z r\nd$ masses t resemble kidneys or bun*es ( grapes 7!n call$ kidney ore72 x also is f\nd z flat cry/als4 ,mo/ ( ! ,texas hematite occurs z granul> or compact masses4 ,"o ( ^! massive v>ieties is compos$ ( %9y scales or plates & is call$ micace\s or specul> hematite4 ,?is v>iety has be5 f\nd 9 ,hudspe? ,c\nty & 9 nor!a/]n ,mason ,c\nty4 ,hematite also commonly occurs z cem5t+ mat]ial 9 _m ,texas s&/ones4 ,"s hematite is =m$ by ! alt]ation ( magnetite1 ano!r iron m9]al4 ,?is hematite is kn[n z m>tite1 & "s ( x /ill has ! cry/al %ape 7an octah$ron or a dodecah$ron7 t belong$ to ! magnetite4 ,mo/ ( ! hematite f\nd 9 ! ,llano uplift area ( c5tral ,texas is believ$ to be alt]$ magnetite4 ,9 ?is c5tral ,texas area1 "s massive1 granul> m>tite has be5 m9$ at ! ,gamble prospect1 a few miles s\!a/ ( ,fr$onia 9 nor!a/]n ,mason ,c\nty1 :]e x occurs z lay]s 9 ,precambrian gneiss4 ,small deposits ( hematite occur 9 o!r p>ts ( ,texas1 too4 ,"s ( ! we/ ,texas localities include ,si]ra ,blanca1 ! ,quitman ,m\nta9s1 & ! ,c>rizo ,m\nta9s ( ,hudspe? ,c\nty & ! area ar\nd ,%aft] 9 ,presidio ,c\nty4 ,holl&ite4 ,see ,manganese ,m9]als4 ,hyalite4 ,see ,opal4 ,jasp]4 ,see ,qu>tz4 ,kaol94 ,see ,clay4 ,lime/one ,lime/one is a s$im5t>y rock made up *iefly ( calcite1 a calcium-c>bonate m9]al4 ,?is rock also commonly conta9s gra9s ( qu>tz1 clay m9]als1 ! m9]al dolomite1 or o!r mat]ials4 ,if a l>ge am\nt ( dolomite is pres5t1 ! rock is call$ dolomitic lime/one4 ,9 "s lime/ones1 ! m9]al gra9s are too small to be di/+ui%$ f ea* o!r )\t a magnify+ glass or a microscope1 b 9 o!r lime/ones1 ! individual m9]al gra9s are easily se54 ,pure lime/one is :ite1 b if x conta9s clay or plant or animal matt] x is light gray1 d>k gray1 or black4 ,lime/one also may be "s %ade ( yell[1 br[n1 or r$4 ,x is fairly s(t & c be scrat*$ ) a knife4 ,because ?is rock conta9s calcite1 an easy *emical te/ w help id5tify x3 a drop or two ( dilute hydro*loric acid w quickly fizz & bubble :5 plac$ on ! lime/one4 ,lime/ones =m 9 fre% wat]1 su* z 9 lakes1 b mo/ ( !m =m 9 ! seas4 ,z "s e>li]-=m$ rocks are wea!r$1 ! calcium m9]als t !y conta9 are dissolv$4 ,creeks & riv]s c>ry ?is dissolv$ mat]ial to ! sea4 ,!re1 small animals1 su* z corals1 cr9oids1 sponges1 & =am9if]s1 take ! dissolv$ mat]ial out ( ! wat] to build _! calcium c>bonate %ells4 ,plants1 su* z algae1 c take calcium c>bonate out ( solution too1 & x collects on !m4 ,%ells1 %ell fragm5ts1 & plant rema9s accumulate on ! sea floor1 =m+ limy deposits t lat] become lime/one4 ,lime/ones also orig9ate 9 a slightly diff]5t way4 ,:5 ! temp]ature & *emical composition ( ! wat] p]mit1 calcium c>bonate precipitates z millions ( t9y gra9s ( calcite & =ms a limy mud t is conv]t$ to lime/one4 ,_m lime/ones conta9 %ell or plant fragm5ts 9 addition to ^! t9y gra9s ( calcite4 ,illu/ration3 ,poli%$ section ( ,l[] ,cretace\s ,edw>ds ,lime/one f ,travis ,c\nty1 ,texas1 conta9+ fossil ga/ropods4 ,!re are sev]al special k9ds ( lime/one4 ,if ! rock is made up ( _m little r\nd$ calcite gra9s t resemble fi% eggs1 x is call$ olitic lime/one4 ,ano!r lime/one1 *alk1 is s(t1 :ite1 & f9e gra9$4 ,x consi/s mo/ly ( t9y %ell fragm5ts & f9e-gra9$ calcite4 ,coqu9a is a por\s lime/one made up ( loosely cem5t$ %ells & %ell fragm5ts4 ,ano!r special k9d ( lime/one1 kn[n z li?ographic lime/one1 because x c be us$ 9 pr9t+1 is smoo?1 firm1 & h>d4 ,its m9]al gra9s are too small to be recogniz$ )\t a microscope4 ,?is k9d ( lime/one breaks ) a smoo?1 sometimes curv$1 fracture4 ,/ill ano!r v>iety1 pulv]ul5t lime/one1 is loose1 s(t1 p[d]y1 & :ite4 ,x occurs 9 ! ,l[] ,cretace\s ,edw>ds ,lime/one 9 ,williamson & ,bell c\nties ( c5tral ,texas4 ,"s ( ?is lime/one is us$ to poli% rice gra9s1 & x is add$ to live/ock fe$s to provide calcium = ! animals4 ,illu/ration3 ,lime/one qu>ry 9 ,l[] ,cretace\s ,edw>ds ,lime/one at ,georget[n1 ,williamson ,c\nty1 ,texas4 ,mu* lime/one is f\nd at ! surface 9 ,texas 9 ,cambrian1 ,ordovician1 ,mississippian1 ,p5nsylvanian1 ,p]mian1 & ,cretace\s =mations4 ,if y w look at numb]s #e1 #f1 #i1 #aj1 & #aa on ! ,texas geologic map 7pp4 #d-e71 y w see t ^! /rata appe> at ! surface 9 c5tral1 nor?-c5tral1 & ,trans-,pecos ,texas4 ,lime/one has _m important uses4 ,mu* ,texas lime/one is cru%$ & us$ z a road-build+ mat]ial & z an aggregate t is mix$ ) cem5t to make concrete4 ,f>m]s 9 "s areas improve _! crops by add+ lime/one to ! soil4 ,lime/one also is s5t to ! iron furnaces 9 ea/ ,texas to be us$ 9 ! production ( pig iron & /eel4 ,"s ( ! ,texas lime/ones are heat$ to a fairly high temp]ature 9 ord] to *ange !m into lime 7calcium oxide74 ,indu/ry uses a l>ge am\nt ( lime 9 mak+ *emicals1 /eel1 glass1 pap]1 & o!r products4 ,build]s use x to make pla/]s1 mort>s1 & /uccos4 ,at plants 9 ,comal1 ,johnson1 ,travis1 & ,williamson c\nties1 lime is made f ,cretace\s lime/ones4 ,ano!r important use ( lime/one is 9 mak+ portl& cem5t4 ,! lime/one is mix$ ) clay or %ale1 & ! mixture is burn$ 9 a kiln until x j beg9s to melt4 ,!n x is all[$ to cool4 ,next1 x is f9ely gr\nd & 9 ord] to keep ! f9i%$ cem5t f h>d5+ or sett+ too quickly :5 x is us$1 a ret>d]1 su* z gypsum1 is add$4 ,a numb] ( cem5t-manufactur+ plants 9 ,texas use ,cretace\s lime/ones1 %ales1 & clays4 ,_m ( ! ,texas lime/ones make excell5t build+ /ones4 ,"s ( !m are qu>ri$ f ,p5nsylvanian & ,cretace\s =mations 9 nor?-c5tral ,texas & f ,l[] ,cretace\s =mations 9 c\nties ne> ! ,llano uplift ( c5tral ,texas4 ,a l>ge qu>ry on ! ,williamson-,travis ,c\nty l9e ne> ,c$> ,p>k 9 c5tral ,texas has suppli$ ,cretace\s lime/one = _m build+s & monum5ts 9 ! ,unit$ ,/ates & ,canada4 ,limonite ,limonite is n really a def9ite m9]al b is a mixture ( iron oxides conta9+ wat]4 ,x is believ$ to be closely relat$ to an iron m9]al call$ goe?ite4 ,"s limonite may be dull & e>?y ) ! appe>ance ( br[ni%-yell[ or ru/y br[n clay4 ,?is v>iety is s s(t t a f+]nail w scrat* x easily4 ,o!r limonite has a d>k br[n or black color & a metallic or almo/ metallic lu/]4 ,a copp] p5ny w n scrat* x1 b a /eel file w4 ,?is k9d ( limonite may h a %9y black surface t resembles glossy lacqu]4 ,! prop]ty t w help y mo/ 9 id5tify+ limonite is ! ru/y1 yell[i%-br[n /reak x leaves :5 rubb$ across a /reak plate4 ,limonite has no cleavage & no cry/al %ape ( its own4 ,b cry/als ( o!r iron m9]als1 su* z pyrite & magnetite1 alt] to =m limonite4 ,x !n occurs ) a cry/al %ape t orig9ally belong$ to "o ( ^! o!r m9]als4 7,su* false =ms ( m9]als are call$ pseudomorphs47 ,limonite also occurs z lay]s 9 rocks1 z holl[ or solid concretions1 or z coat+s on o!r m9]als4 ,x is f\nd mix$ ) m9]als su* z clays & s]ves z ! cem5t+ mat]ial 9 "s s&/ones4 ,limonite is f\nd 9 _m localities 9 ,texas includ+ ,blanco1 ,brew/]1 ,burnet1 ,llano1 & ,san ,saba c\nties4 ,! mo/ important limonite deposits 9 ,texas1 h[ev]1 are 9 ! ea/]n "p ( ! ,/ate1 p>ticul>ly 9 ,&]son1 ,cass1 ,*]okee1 ,h5d]son1 ,m>ion1 ,morris1 ,nacogdo*es1 ,smi?1 & ,up%ur c\nties4 ,! ea/ ,texas limonite deposits occur ma9ly 9 ,we*es s$im5t>y rocks4 ,^! rocks1 :i* 7 deposit$ 9 ! sea dur+ ,eoc5e ,t]ti>y "t1 conta9 clay along ) gre5s&s4 7,gre5s&s are small1 s(t gra9s t conta9 glauconite1 a m9]al compos$ ( iron1 silicon1 & sev]al o!r elem5ts47 ,lat]1 z ! sea retreat$1 ^! s$im5ts became a "p ( ! l&4 ,wat]s seep+ ?r\gh ! s$im5ts *ang$ into weak solutions ( c>bonic & sulfuric acid t dissolv$ ! iron out ( "s ( ! gre5s&s4 ,:5 conditions 7 favorable1 ?is iron 0 re-deposit$ z an iron-c>bonate m9]al call$ sid]ite4 ,sid]ite 0 *ang$ to limonite by wea!r+4 ,"s sid]ite is /ill f\nd 9 ea/ ,texas1 & x is also m9$ along ) ! limonite z an iron ore4 ,ea/ ,texas iron ore has be5 m9$ f "t to "t ev] s9ce ab\t #ahee1 & records %[ t a numb] ( local iron furnaces once op]at$4 ,! br[n iron ore 7z ! limonite is also call$7 n[ is m9$ f op5 pits 9 ,cass1 ,*]okee1 & ,morris c\nties4 ,?is ore1 aft] be+ wa%$1 goes into bla/ furnaces at ,lone ,/> 7ne> ,da+]field7 & at ,h\/on4 ,9 ! bla/ furnaces ! ore is *ang$ into metallic iron by mix+ x ) coke 7made f coal7 & lime/one & bl[+ 9 bla/s ( hot air4 ,to make /eel1 ! iron f ! bla/ furnace 7call$ pig iron7 is put into op5-he>? furnaces toge!r ) scrap iron1 lime/one1 & o!r mat]ials4 ,?is mixture is heat$ & melt$ toge!r to get rid ( unwant$ sub/ances4 ,!n o!r elem5ts1 su* z molybd5um1 manganese1 or nickel1 are add$ to make /eel ) ! "r /r5g? & t\ghness4 ,illu/ration3 ,limonite ore is *ang$ to metallic iron 9 a bla/ furnace4 ,skip c> ,hot ,gases ,bla/ ,furnace ,iron ,ore ,lime/one ,coke ,fire ,brick l9+ ,/eel ,plate cov]+ #ceej;,f ,hot ,air ,bla/ ,slag ,slag ,ladle ,molt5 ,iron ,iron ,ladle ,/eel mills alongside ! furnaces 9 ,texas turn out _m products1 su* z /eel plates = oil tanks1 %ips1 & tank c>s & /eel beams = framework 9 build+s & bridges4 ,"s ( _! o!r products include pipes = ! oil & *emical indu/ries & wire = nails & f5c+ mat]ial4 ,li?ographic ,lime/one4 ,see ,lime/one4 ,llanite ,llanite is a unique rock t is f\nd only 9 ,llano ,c\nty 9 c5tral ,texas4 ,?is intrusive igne\s rock is made up ( easily se5 cry/als & gra9s ( qu>tz & feldsp> t are scatt]$ ?r\gh a br[n-color$ mass ( extremely small m9]al gra9s4 ,! qu>tz is beautiful1 sky-blue1 & opal-l2 ! feldsp> has a ru/y p9k color4 7,because ! qu>tz looks l opal1 ?is rock (t5 is call$ opal9e granite47 ,! m9]al gra9s t make up ! br[n-color$ mass are s t9y t !y c be id5tifi$ only ) a microscope4 ,!y are qu>tz1 feldsp>1 mica1 fluorite1 & apatite4 ,llanite =m$ dur+ ,precambrian "t4 ,molt5 rock mat]ial =c$ its way upw>d into cracks t cut across granite & s*i/ rocks :ile ! rocks 7 /ill f> und]gr\nd4 ,?is hot magma rema9$ 9 ! cracks :]e x cool$ & h>d5$ to =m long1 n>r[1 wall-l masses 7call$ dikes7 ( llanite4 ,we c see "s ( ! llanite dikes expos$ at ! e>?'s surface to ! nor? & nor!a/ ( ,llano 9 ,llano ,c\nty because ! ov]ly+ rocks h wea!r$ away4 ,llanite has be5 qu>ri$ f "o ( ! dikes we/ ( ,babyhead 9 nor!rn ,llano ,c\nty4 ,because llanite is bo? attractive & /rong1 x has be5 us$ z an ornam5tal /one & z a monum5t /one4 ,magnetite ,magnetite1 iron oxide1 is a black1 metallic m9]al ) an out/&+ physical prop]ty3 x is magnetic--fragm5ts ( magnetite readily cl+ to a magnet4 ,x also leaves a black /reak :5 rubb$ across a /reak plate4 ,al?\gh ?is m9]al is too h>d to be scrat*$ by ! av]age pocket knife1 a /eel file w scrat* x4 ,magnetite is fairly heavy--x has a specific gravity ( #e4ah4 ,magnetite occurs z compact or granul> masses1 z scatt]$ gra9s1 & z cry/als4 ,mo/ ( ! cry/als are octah$rons1 b "s dodecah$rons are f\nd4 ,magnetite helps make up a "p ( _m metamorphic & igne\s rocks1 & x also occurs z t9y cry/als & gra9s 9 "s s&s1 s&/ones1 & o!r s$im5t>y rocks4 ,illu/ration3 ,metallic iron1 aft] leav+ ! bla/ furnace1 is made into /eel 9 an op5-he>? furnace4 ,op5-,he>? ,furnace ,scrap metal ,alloy+ ,elem5ts ,lime/one ,furnace ,int]ior ,live ,fuel ,burn] ,air pre-heat$ ,mo/ ( ! magnetite t has be5 f\nd 9 ,texas occurs 9 ,precambrian gneiss & s*i/ rocks ( ! ,llano uplift area ( c5tral ,texas1 p>ticul>ly 9 ,llano ,c\nty & 9 ea/]n ,mason ,c\nty4 ,x occurs z ?9 lay]s1 z ?ick l5s-%ap$ deposits1 & z scatt]$ gra9s 9 ! rocks4 ,probably at lea/ a billion ye>s ago ^! gneisses & s*i/s 7 s$im5t>y rocks1 su* z %ales & s&/ones4 ,"s geologi/s believe t ^! rocks c\ld h conta9$ iron s$im5ts 7p]haps 9 ! =m ( glauconite74 ,great =ces bel[ ! e>?'s surface crumpl$ & squeez$ ! s$im5t>y rocks & *ang$ !m into ! metamorphic s*i/ & gneiss rocks we see today4 ,z ?is happ5$1 ! iron s$im5ts 9 ! rocks 7 *ang$ into magnetite4 ,illu/ration3 ,granul> magnetite fragm5ts f nor?we/ ( ,llano1 ,llano ,c\nty1 ,texas1 are attract$ to a magnet4 ,at lea/ "s ( ! magnetite 9 ?is area 7su* z ! deposit at ,iron ,m\nta9 9 ,llano ,c\nty7 probably _h a diff]5t sort ( orig94 ,molt5 igne\s rock mat]ial conta9+ iron c\ld h mov$ up into cracks 9 ! anci5t s$im5t>y rocks4 ,!n ! magnetite =m$ f ?is iron mat]ial :5 ! igne\s & s$im5t>y rocks 7 *ang$ into ! s*i/s & gneisses ( today4 ,none ( ! ,llano & ,mason ,c\nty magnetite deposits is really v l>ge4 ,nev]!less1 prospect+ & a little m9+ h be5 c>ri$ on f "t to "t at sev]al deposits 9 ?is area4 ,at ,iron ,m\nta91 :i* is ab\t #ab miles nor?we/ ( ,llano 9 ,llano ,c\nty1 magnetite has be5 m9$ f op5 pits4 ,al?\gh magnetite is commonly us$ z a s\rce ( iron1 ! magnetite f ?is deposit 0 us$ z a heavy concrete aggregate4 ,mala*ite4 ,see ,copp] ,m9]als4 ,manganese ,m9]als 7,braunite1 ,holl&ite1 ,pyrolusite7 ,al?\gh manganese does n occur alone 9 nature z a native elem5t1 x makes up a "p ( _m m9]als & comp\nds4 ,?is elem5t has an important use 9 /eel mak+1 :]e x helps rid ! /eel ( unwant$ sub/ances1 su* z oxyg5 & sulfur1 &1 9 addition1 x is us$ to make t\gh1 h>d1 manganese /eel = armor plate1 railroad tracks1 safes1 & /eam %ovels4 ,manganese has v>i\s uses outside ! /eel indu/ry4 ,x is add$ to copp] & nickel to make alloys1 x is us$ 9 ! manufacture ( dry-cell batt]ies1 & 7z manganese sulfate7 x is us$ z a f]tiliz]4 ,manganese m9]als & comp\nds1 su* z braunite1 holl&ite1 pyrolusite1 & wad1 occur 9 sev]al c\nties 9 ,texas4 ,no l>ge1 comm]cial deposits h be5 f\nd "h4 ,"s manganese comp\nds & m9]als are cov]$ ) a s(t1 sooty black mat]ial t w soil y\r f+]s4 ,?is c help y recognize ^! m9]als2 h[ev]1 a few non-manganese m9]als1 su* z "s *alcocite1 also h a black coat+ t soils y\r f+]s 9 a simil> way4 ,"o ( ! manganese m9]als1 braunite1 is a complex oxide ( manganese t conta9s silica4 ,x has a submetallic lu/] & is d>k /eel-gray or black4 ,:5 rubb$ across a /reak plate1 x leaves a /eel-gray or a black /reak4 ,?is m9]al is too h>d to be scrat*$ by a pocket knife1 b a piece ( qu>tz or a /eel file w scrat* x4 ,braunite has a specific gravity ( #d4ge to #d4hb4 ,x has f\r directions ( cleavage t are p>allel to ! faces ( a pyramid4 ,9 ! ,spill] m9e1 ab\t #ae miles nor!a/ ( ,mason 9 ,mason ,c\nty1 masses ( braunite occur z l5s-%ap$ lay]s 9 ,precambrian gneiss & qu>tzite rocks4 ,?is braunite may h =m$ f ano!r manganese m9]al 7possibly manganese g>net7 t 0 expos$ at ! e>?'s surface aft] ! ov]ly+ rocks erod$ away4 ,z ?is o!r m9]al wea!r$1 x may h alt]$ into braunite1 or ! braunite c\ld h be5 deposit$ f solutions emanat+ f hot magmas be=e ! great ?ickness ( ov]ly+ rock 0 remov$4 ,! m9]al v>iety holl&ite is a r>e manganate ( manganese & b>ium4 ,x has a metallic lu/]1 & its color is silv]y gray or black4 ,:5 y rub x across a /reak plate1 holl&ite leaves a black /reak4 ,x has a specific gravity ( #d4g to #e4 ,holl&ite is r h>d1 b a /eel file w scrat* x4 ,illu/ration3 ,holl&ite f ,jeff ,davis ,c\nty1 ,texas4 ,holl&ite occurs 9 we/]n ,jeff ,davis ,c\nty 9 we/ ,texas at :at is call$ ! ,mayfield prospect4 ,"h1 x is f\nd z r\nd$ masses t occur 9 a ve9 ne> a l>ge fault 9 ,l[] ,cretace\s lime/one rocks4 ,o!r manganese comp\nds1 pyrolusite & wad1 are f\nd 9 sev]al important deposits ne> ! ,pecos ,riv] 9 we/]n ,val ,v]de ,c\nty4 ,pyrolusite is a manganese dioxide m9]al4 ,x is black1 opaque1 & s s(t t x rubs (f on y\r f+]s l soot4 ,pyrolusite may be granul> & massive or may be p[d]y4 ,x also occurs z a f]n-l coat+ on rocks4 ,wad is n really a m9]al b is an impure1 dull-black or br[ni%-black mixture ( manganese oxide1 wat]1 & o!r sub/ances4 ,x c be s(t en\gh to soil y\r f+]s1 or x c be too h>d to scrat* ) a pocket knife4 ,wad occurs 9 e>?y or compact masses or 9 cru/s or /a9s on rocks4 ,9 ,val ,v]de ,c\nty1 ! wad & pyrolusite are f\nd mix$ ) soil1 clay1 gravel1 s&1 & plant rema9s4 ,?is mat]ial fills cracks 9 ,l[] ,cretace\s lime/ones1 x is scatt]$ ?r\gh gravels1 & x is deposit$ 9 l[ places at ! surface4 ,! manganese 9 ^! deposits came f lime/one rocks t h s9ce wea!r$ away4 ,ra9wat] trickl$ into ^! rocks & dissolv$ ! manganese m9]als !y conta9$4 ,?is manganese 0 wa%$ d[n t[>d ! ,pecos ,riv] & 0 deposit$ z wad & pyrolusite4 ,m>ble ,m>ble is a metamorphic rock made up *iefly ( sp>kl+ gra9s ( calcite or dolomite1 b o!r m9]als may be pres5t4 ,! m>ble may be f9e gra9$1 m$ium gra9$1 or co>se gra9$2 commonly1 all ! m9]al gra9s are ab\t ! same size4 ,m>ble may be ( uni=m color1 b&$1 spott$1 or /reak$4 ,if x is made up only ( pure calcite or dolomite1 ! m>ble is :ite4 ,if1 h[ev]1 x conta9s c>bonace\s mat]ial1 su* z graphite1 x is grayi% or black4 ,limonite impurities cause ! m>ble to be yell[i% br[n1 & manganese oxides & hematite give x a br[ni%1 p9ki%1 or r$di% color4 ,m>ble is a r s(t rock1 & y c scrat* x easily ) a pocket knife4 ,a few drops ( dilute hydro*loric acid w bubble & fizz readily on calcite m>ble2 on dolomite m>ble1 x may fizz slightly4 ,m>ble =ms f lime/one or f dolomite rock4 ,heat & pressure bel[ ! e>?'s surface cause ! calcite & dolomite m9]al gra9s 9 ^! rocks to recry/allize4 ,a f9e-gra9$ lime/one c be *ang$ into a co>se-gra9$ calcite m>ble4 ,! m>ble is n made up ( new & diff]5t m9]als1 b x has a new texture unlike t ( ! lime/one4 7,to a build]1 ! ^w m>ble has ano!r mean+4 ,he consid]s rocks su* z unalt]$ lime/one1 unalt]$ dolomite1 or ev5 s]p5t9e to be m>ble1 if !y w take a high poli%47 ,illu/ration3 ,poli%$ section ( ,precambrian metamorphic m>ble f ,llano ,c\nty1 ,texas4 ,metamorphic m>bles occur at ! surface 9 c5tral ,texas & 9 we/ ,texas4 ,"s ( ! we/ ,texas occurr5ces are 9 ! ,van ,horn area ( ,culb]son & ,hudspe? c\nties & 9 ! ,big ,b5d area ( ,brew/] ,c\nty4 ,9 c5tral ,texas1 ,precambrian m>bles are f\nd 9 ,burnet1 ,gillespie1 ,llano1 & ,mason c\nties ( ! ,llano uplift area4 ,_m ( !m are suitable = use z monum5t & build+ /ones4 ,"s ( ! ,llano ,c\nty m>ble is qu>ri$ & us$ z granules = ro(s & z t]razzo *ips = mak+ colorful floors 7describ$ ) s]p5t9e on p4 #hh74 ,m>tite4 ,see ,hematite4 ,mica ,mica is n j "o m9]al b is ! "n giv5 to a gr\p ( simil> m9]als4 ,! mica m9]als are easy to recognize4 ,because !y h p]fect cleavage 9 "o direction1 !y split into ?91 flat %eets4 ,y c see ?r\gh "s mica %eets1 & !y are ela/ic en\gh to be b5t back & =?4 7,ano!r m9]al1 sel5ite gypsum1 also w split into ?91 flat1 transp>5t %eets1 b sel5ite %eets break :5 y b5d !m47 ,illu/ration3 ,mica m9]als h p]fect cleavage 9 "o direction1 result+ 9 ?91 %eet-l cleavage fragm5ts4 ,basal ,cleavage ,two ( ! mica m9]als t y are mo/ likely to f9d 9 ,texas are muscovite & biotite4 ,bo? ^! m9]als are potassium-alum9um silicates1 & biotite1 9 addition1 conta9s magnesium & iron4 ,9 g5]al1 muscovite is light color$1 t is1 x has a light br[n1 yell[1 or gre5 t9t1 or is colorless1 & biotite is d>k color$1 commonly d>k gre51 br[n1 or black4 ,^! m9]als h glassy or pe>ly lu/]s & are r s(t--a copp] p5ny scrat*es !m4 ,! specific gravity ( biotite is #b4h to #c4b1 & t ( muscovite is #b4gf to #c4a4 ,mica m9]als occur 9 igne\s rocks1 su* z granite & pegmatite1 & 9 metamorphic rocks1 su* z s*i/ & gneiss4 ,!y also are f\nd z t9y flakes 9 "s s&/ones1 lime/ones1 & o!r s$im5t>y rocks4 ,mo/ ( ! ,texas mica is f\nd 9 ! ,llano uplift area 7p>ticul>ly 9 ,llano ,c\nty7 & 9 ! ,mica ,m9e area4 7,! ,mica ,m9e area is 9 ! ,van ,horn ,m\nta9s ab\t #ae miles s\? ( ,van ,horn 9 we/ ,texas47 ,9 bo? ^! areas1 ! mica m9]als occur mo/ly 9 ,precambrian pegmatites & mica s*i/s4 ,! gleam+ mica s*i/s 7 once igne\s rocks or s$im5t>y rocks su* z s&/ones & %ales4 ,long ago1 great =ces b5ea? ! e>?'s surface *ang$ ! rocks into mica s*i/s4 ,! mica t is f\nd 9 pegmatites =m$ f hot fluids ( igne\s orig9 :5 ! pegmatite rock itself 0 =m$4 ,clu/]s ( mica 9 ! pegmatites are call$ books1 because ! ?9 %eets into :i* ! mica splits look l pages4 ,"s muscovite books up to #h in*es across are f\nd 9 ! ,mica ,m9e area ( ! ,van ,horn ,m\nta9s4 ,! books or %eets ( muscovite mica t occur 9 pegmatites are especially valuable to indu/ry4 ,muscovite c /& great heat )\t melt+1 x is t\gh1 x splits into ?9 %eets1 & x lets v little heat & electricity pass ?r\gh4 ,because ( ^! prop]ties1 muscovite is us$ 9 fuses & z insulators 9 heat+ elem5ts ( electric irons & toa/]s4 7,biotite is n us$1 because ! iron x conta9s makes x a conductor ( electricity47 ,%eet muscovite also is widely us$ by ! electronics indu/ry z a non-conduct+ mat]ial 9 ! manufacture ( tubes & o!r products4 ,bo? muscovite & biotite f mica s*i/ rocks1 z well z scrap pieces ( %eet mica f pegmatites1 are gr\nd into flakes or p[d]4 ,?is gr\nd-up mica has _m uses1 rang+ f a p[d] coat+ = automobile inn]-tubes to ,*ri/mas tree 8sn[40 ,only a small am\nt ( mica has be5 m9$ 9 ,texas4 ,a fair grade ( %eet mica occurs 9 ! pegmatites at ,mica ,m9e 9 we/ ,texas1 b ! deposit is n l>ge4 ,9 ! pegmatites ( ! ,llano uplift area ( c5tral ,texas1 no %eet mica has be5 f\nd t is consid]$ good en\gh = ! requirem5ts ( indu/ry4 ,mica suitable = gr9d+1 h[ev]1 is f\nd 9 bo? ^! ,texas areas4 ,micace\s ,hematite4 ,see ,hematite4 ,microcl9e4 ,see ,feldsp>4 ,milky ,qu>tz4 ,see ,qu>tz4 ,muscovite4 ,see ,mica4 ,native ,silv]4 ,see ,silv] ,m9]als4 ,obsidian & ,vitrophyre ,obsidian is a d>k1 glassy-look+ igne\s rock4 ,mo/ obsidian conta9s ! same *emical elem5ts z granite & rhyolite1 s9ce all ?ree ( ^! rocks c =m f ! same type ( molt5 rock mat]ial4 ,obsidian1 h[ev]1 has no sep>ate m9]als1 because its *emical elem5ts are n comb9$ 9 an ord]ly way4 ,x is a natural glass4 ,because x is a glass1 we "k t obsidian =ms v quickly4 ,"o way = x to =m is f ! sudd5 cool+ ( hot1 molt5 lava t fl[s out ( volcanoes4 ,if ! lava cools & h>d5s be=e ! sep>ate m9]als c cry/allize1 x becomes a natural glass1 su* z obsidian4 ,?is rock is smoo? & %9y4 ,mo/ ( x is black1 b "s c be d>k gre5 or d>k br[n4 ,obsidian all[s light to pass ?r\gh x1 & x breaks ) a curv$1 con*oidal fracture4 ,! brok5 edges are v %>p4 ,ano!r glassy igne\s rock t =ms f fa/-cool+ lava is vitrophyre4 ,x looks l obsidian except t x has cry/als or cry/all9e m9]al gra9s 7:i* may be light color$7 scatt]$ ?r\gh ! d>k glassy mat]ial4 ,illu/ration3 ,obsidian 0 us$ by ! ,indians to make arr[heads4 ,obsidian & vitrophyre are f\nd 9 ! ,big ,b5d area ( ,brew/] & ,presidio c\nties 9 we/ ,texas4 ,!y occur ) o!r igne\s rocks t =m$ !re dur+ ,t]ti>y "t4 ,! ,indians :o long ago roam$ ?is area us$ ! smoo?1 %9y vitrophyre & obsidian to make "s ( _! arr[heads & scrap]s4 ,today1 rock collectors pick up ^! attractive rocks = _! collections1 & "s ( !m cut & poli% obsidian & vitrophyre = use z gem/ones4 ,onyx4 ,see ,qu>tz4 olitic ,lime/one4 ,see ,lime/one4 ,opal ,opal is l h>d5$ jelly or gelat94 ,x has no cry/all9e inn] /ructure & no cry/al %ape ( its own--x is amorph\s4 ,?is m9]al has almo/ ! same *emical composition z qu>tz4 ,bo? are silicon dioxides 7silica71 b opal1 9 addition1 conta9s wat]4 ,opal c be almo/ any color--r$1 yell[1 blue1 br[n1 gray1 :ite--or x c be colorless4 ,x is transp>5t or transluc5t & appe>s glassy1 res9\s1 greasy1 or dull4 ,opal has a specific gravity ( #a4i to #b4b--?is m9]al is a little light] ?an qu>tz4 ,x also is s(t] ?an qu>tz4 ,a copp] p5ny w n scrat* opal1 b qu>tz w4 ,opal has a :ite /reak & a curv$1 con*oidal fracture b no cleavage4 ,opal occurs 9 a numb] ( places 9 ,texas4 ,9 ! ,trans-,pecos c\ntry ( we/ ,texas1 x fills cracks & cavities 9 "s ( ! extrusive igne\s rocks4 ,x occurs on ! ,high ,pla9s ( nor?we/ ,texas1 & x is f\nd 9 ,t]ti>y =mations ( ! ,gulf ,coa/al ,pla9 :]e x occurs z masses t fill cracks & cavities 9 s$im5t>y rocks1 z ! cem5t+ mat]ial 9 "s s&/ones 7su* z 9 ! ,catah\la s&/one71 & z opaliz$ wood4 ,mu* opal =ms f und]gr\nd wat]s t conta9 silicon4 ,^! solutions move ?r\gh ! rocks & deposit ! opal 9 !m4 ,opal is f\nd 9 a numb] ( v>ieties4 ,"s %[ a beautiful1 lu/r\s play ( colors t comes f inside ! specim5s4 ,^! v>ieties are kn[n z preci\s opal & are priz$ z gem/ones4 ,9 ,texas1 "s preci\s opal is f\nd ne> ,alp9e 9 ,brew/] ,c\nty4 ,x has a milky :ite to blui%-:ite color1 is transluc5t1 & %[s a fi]y orange1 r$1 blue1 & gre5 play ( colors4 ,! v>iety kn[n z common opal %[s no play ( colors4 ,x may be :ite1 gray1 blui%1 r$di%1 gre5i%1 or yell[i%1 & x is only slightly transluc5t4 ,x is f\nd 9 ,brew/]1 ,jeff ,davis1 ,presidio1 & o!r c\nties ( ! ,trans-,pecos c\ntry ( we/ ,texas4 ,x occurs also ar\nd "s ( ! wet-wea!r 7playa7 lakes on ! ,texas ,high ,pla9s4 ,9 ! ,gulf ,coa/al ,pla91 common opal is f\nd ) *alc$ony 7a v>iety ( qu>tz7 9 ,t]ti>y =mations4 ,a s\? ,texas locality sometimes visit$ by collectors is ne> ,fre] 9 ,duval ,c\nty4 ,a cle>1 commonly r\nd$1 v>iety ( opal t looks l ice is call$ hyalite4 ,two areas 9 :i* x has be5 f\nd are 9 ,presidio ,c\nty 9 we/ ,texas & 9 ,llano ,c\nty 9 c5tral ,texas4 ,illu/ration3 ,opaliz$ wood f ,wa%+ton ,c\nty1 ,texas4 ,a v>iety ( petrifi$ wood1 call$ opaliz$ wood1 is opal t replac$ ! fib]s ( a piece ( wood4 ,wood opal is f\nd at a numb] ( places 9 ! ,gulf ,coa/al ,pla94 ,x occurs !re 9 ,t]ti>y =mations )9 ab\t #bj miles ( ! b\nd>y l9e betwe5 areas #b & #c %[n on ! geologic map 7pp4 #d-e74 ,a s(t opal9e mat]ial call$ diatomite1 or diatomace\s e>?1 is made up *iefly ( ! skeletons ( diatoms--t9y1 "o-cell$ plants t live 9 fre% or salt wat]4 ,^! little plants are able to take silica f ! wat] to make opal skeletons = !mselves4 ,:5 ! diatom skeletons collect at ! bottom ( a lake or sea1 !y =m ! light1 crumbly1 :ite1 gray1 or cream-color$ deposit ( impure opal kn[n z diatomite4 ,indu/ry uses ?is mat]ial z a filt]1 z insulation1 z an abrasive1 & z a fill]4 ,diatomite =m$ 9 anci5t lakes on ! ,texas ,high ,pla9s dur+ late ,t]ti>y 7,plioc5e7 & e>ly ,quat]n>y 7,plei/oc5e7 times4 ,x is f\nd 9 ,arm/rong1 ,crosby1 ,dick5s1 ,ector1 ,h>tley1 & ,lamb c\nties4 ,opal9e ,granite4 ,see ,llanite4 ,or?oclase4 ,see ,feldsp>4 ,pegmatite ,pegmatites occur 9 igne\s rock areas1 & mo/ geologi/s consid] !m intrusive igne\s rocks4 ,!y are made up ( cry/als & cry/all9e m9]al gra9s t fit toge!r--! gra9s are int]lock$4 ,! cry/als & gra9s 9 pegmatites are l>g] ?an ^? ( surr\nd+ rocks1 & "s are huge1 ev5 l>g] ?an a man4 ,h[ev]1 !re is a wide range ( gra9 sizes 9 pegmatite4 ,"s pegmatites cut ?r\gh igne\s or metamorphic rocks 9 su* a way t !y resemble walls 7call$ dikes74 ,o!rs are f\nd z ve9s1 z flat masses1 or z odd-%ap$ bodies 9 rocks4 ,_m pegmatites occur 9 granites & conta9 feldsp>1 qu>tz1 mica1 & o!r m9]als1 z granite does4 ,"s pegmatites occur ) o!r k9ds ( igne\s rocks & conta9 ! same m9]als z ^! rocks4 ,a few pegmatites conta9 r>e & unusual m9]als4 ,_m geologi/s believe t pegmatites =m f hot fluids ( igne\s orig9 t are left aft] o!r igne\s rocks1 su* z granite1 h already =m$4 ,^! left-ov] fluids conta9 l>ge am\nts ( alum9um1 potassium1 silicon1 sodium1 & sev]al o!r elem5ts4 ,:ile ! granite or o!r rocks are /ill f> und]gr\nd1 ?is mat]ial pu%es up into !m1 & may ev5 p>tly dissolve !m4 ,!n x sl[ly cools & h>d5s into pegmatite4 ,x is believ$ t1 lat]1 m fluids move into cracks 9 "s pegmatites4 ,?is new mat]ial adds o!r m9]als to ! pegmatites & alt]s "s ( ^? m9]als already !re4 ,illu/ration3 ,qu>tz-feldsp> pegmatite f ,burnet ,c\nty1 ,texas4 ,"s ( ! pegmatites we n[ see at ! surface 9 ,texas are probably ab\t a billion ye>s old4 ,!y =m$ dur+ ,precambrian "t & occur ) o!r extremely old rocks4 ,"o well-kn[n ,texas pegmatite area is ! ,mica ,m9e di/rict ( we/ ,texas4 ,x is ab\t #ae miles s\? ( ,van ,horn 9 ! ,van ,horn ,m\nta9s ( ,culb]son & ,hudspe? c\nties4 ,ano!r pegmatite area is 9 ! ,llano uplift ( c5tral ,texas4 ,^! c5tral ,texas pegmatites occur 9 ,burnet1 ,gillespie1 ,llano1 & ,mason c\nties4 ,l>ge cry/als & gra9s ( feldsp>1 mica1 & qu>tz are f\nd 9 ! pegmatites ( bo? ^! areas4 ,a small am\nt ( mica has be5 m9$ f ! we/ ,texas pegmatites1 & feldsp> has be5 produc$ f ! c5tral ,texas pegmatites4 ,an extremely r>e & unusual pegmatite occurs 9 ! ,llano uplift area at ,b>+] ,hill1 :i* is we/ ( ,burnet 9 ,llano ,c\nty4 ,?is pegmatite 0 once on ! bank ( ! ,colorado ,riv]1 b :5 ,bu*anan ,dam 0 built1 ! area 0 flood$4 ,! ,b>+] ,hill pegmatite n[ lies b5ea? ! wat] ( ,lake ,bu*anan4 ,_m r>e m9]als1 :i* conta9 b]yllium1 c]ium1 ?orium1 uranium1 yttrium1 zirconium1 & a numb] ( o!r elem5ts1 occur 9 ?is pegmatite4 ,"s ( ^! m9]als1 su* z ^? conta9+ yttrium & zirconium1 gl[ or inc&esce :5 !y are heat$4 ,dur+ ! e>ly "p ( ?is c5tury1 be=e ! area 0 flood$1 sev]al ( ! yttrium m9]als 7 m9$ & us$ 9 mak+ lamp mantles4 ,pit*bl5de4 ,see ,uranium ,m9]als4 ,preci\s ,opal4 ,see ,opal4 ,pulv]ul5t ,lime/one4 ,see ,lime/one4 ,pumicite4 ,see ,volcanic ,a%4 ,pyrite ,pyrite is a %9y1 pale gold5-yell[ or brassy-yell[ metallic m9]al4 ,?is m9]al1 an iron disulfide1 is s (t5 mi/ak5 = gold t x is widely kn[n by ! nickname fool's gold4 ,except = _! simil> color & lu/]1 pyrite & gold are really v diff]5t4 ,:5 y rub pyrite across a /reak plate1 x leaves a black1 a gre5i%-black1 or a br[ni%-black /reak1 b ! /reak ( gold is gold-color$4 ,pyrite is too h>d = ! av]age pocket knife to scrat*1 b a knife w scrat* gold easily4 ,pyrite is brittle & readily breaks1 b gold is malleable & flatt5s out :5 hit ) a hamm]4 ,pyrite is only ab\t #e times z heavy z an equal volume ( wat]1 b pure gold is ov] #ai times z heavy4 ,& pyrite may h a br[n or a multicolor$ t>ni% on x1 b gold nev] t>ni%es4 ,illu/ration3 ,pyrite ve9s 9 :ite m>ble f ,llano ,c\nty1 ,texas4 ,illu/ration3 ,cubic cry/als ( pyrite4 ,pyrite is a common m9]al & is f\nd 9 _m ( ! igne\s1 metamorphic1 & s$im5t>y rocks ( ,texas4 ,x may be scatt]$ ?r\gh ! rocks1 or x may fill cracks & cavities 9 !m4 ,?is m9]al occurs z granul> & compact masses1 z r\nd$ masses1 or z cry/als4 ,! cry/als are commonly cubes1 pyritoh$rons1 or octah$rons4 ,9 "s cry/als1 ! %apes are comb9$ 7su* z a cube ) an octah$ron or two pyritoh$rons gr[n ?r\gh ea* o!r74 ,y may notice t ! sides ( "s cubes & pyritoh$rons h f9e1 p>allel grooves 7call$ /riae or /riations7 on !m4 ,pyrite orig9ates 9 a numb] ( diff]5t ways4 ,"s ( x =ms1 along ) o!r m9]als 9 igne\s rocks1 f hot magmas4 ,x also =ms 9 metamorphic rocks by ! same processes t produce ^! rocks4 ,"s ( ! pyrite 9 lime/one & o!r s$im5t>y rocks is =m$ :5 ! rocks !mselves are deposit$ by seas or /reams4 ,pyrite also is deposit$ by ! hot fluids t are giv5 (f by magmas4 ,^! fluids travel up into cracks & o!r op5+s 9 rocks & !n =m pyrite z well z o!r m9]als4 ,mu* pyrite =ms 9 /ill ano!r way4 ,z wat] seeps ?r\gh rocks1 x dissolves "s ( ! iron m9]als t !y conta94 ,:51 "u c]ta9 conditions1 ^! iron solutions mix ) hydrog5 sulfide 7?is is ! gas t makes "s wat] smell l rott5 eggs71 pyrite is =m$4 ,pyrite alt]s easily4 ,because ( ?is1 mo/ build]s c>efully *eck ! lime/one1 granite1 m>ble1 or :atev] o!r build+ /one !y plan to use to be sure t x does n conta9 l>ge am\nts ( pyrite4 ,:5 expos$ to ! wea!r1 pyrite *anges to limonite & causes an unsightly ru/ /a94 ,pyrite is us$ z a s\rce ( sulfur1 & x is produc$ = ?is purpose 9 sev]al /ates4 ,9 ,texas1 h[ev]1 no pyrite deposits h be5 f\nd t are l>ge en\gh to be m9$4 ,pyrolusite4 ,see ,manganese ,m9]als4 ,qu>tz ,qu>tz1 silicon dioxide1 is "o ( ! mo/ common m9]als4 ,x is glassy1 waxy1 greasy1 or dull & is transp>5t or transluc5t4 ,pure qu>tz is colorless1 b impurities make "s v>ieties :ite1 black1 or a %ade ( r$1 yell[1 blue1 violet1 or br[n4 ,qu>tz is a h>d m9]al4 ,x scrat*es w9d[ glass & _c be scrat*$ by a pocket knife or ev5 by a /eel file4 ,x has a specific gravity ( #b4fe4 ,! curv$1 con*oidal fracture %[n by _m specim5s helps id5tify x4 ,qu>tz is pl5tiful 9 ,texas4 ,x occurs 9 igne\s rocks1 su* z granite1 llanite1 & pegmatite2 9 metamorphic rocks1 su* z qu>tzite1 s*i/1 & gneiss2 & 9 s$im5t>y rocks1 su* z "s s&/one1 conglom]ate1 & breccia4 ,illu/ration3 ,qu>tz cry/al1 ) inclusions1 f ,burnet ,c\nty1 ,texas4 ,qu>tz is f\nd z cry/als & z masses4 ,"s ( ! masses are co>sely cry/all9e1 b "s are made up ( extremely small cry/all9e p>ticles call$ cryptocry/all9e qu>tz4 ,"s ( ! cryptocry/all9e v>ieties ( qu>tz f\nd 9 ,texas are *alc$ony1 *]t1 & jasp]4 ,"s ( ! co>sely cry/all9e v>ieties f\nd "h are ame?y/1 milky qu>tz1 rose qu>tz1 smoky qu>tz1 & rock cry/al4 ,illu/ration3 ,ame?y/ geode f ! ,alp9e area ( ,brew/] ,c\nty1 ,texas4 ,a colorless1 glassy v>iety ( qu>tz1 call$ rock cry/al1 is cle> en\gh to see ?r\gh4 ,x is f\nd z cry/als t are #f-sid$ prisms ) pyramid-l faces on ! ends4 ,?is v>iety is commonly associat$ ) igne\s rocks1 su* z ^? ( ! ,llano uplift area ( c5tral ,texas & ( ! ,trans-,pecos c\ntry ( we/ ,texas4 ,x is commonly us$ z a gem/one & is made into necklaces1 e>r+s1 & o!r jewelry4 ,"s specim5s ( rock cry/al h sl5d]1 ne$le-l cry/als ( o!r m9]als1 su* z t\rmal9e1 act9olite1 or rutile1 enclos$ 9 !m4 ,a cle>1 glassy v>iety ( qu>tz1 ame?y/1 has a purple or violet color4 ,x1 l rock cry/al1 is commonly f\nd 9 #f-sid$ prisms ) pyramid-%ap$ ends & is also priz$ z a gem/one4 ,ame?y/ has be5 f\nd 9 ,precambrian rocks 9 ! ,llano uplift area ( c5tral ,texas4 7,ame?y/ ,hill1 a locality well kn[n to collectors = _m ye>s1 is 9 nor!a/]n ,gillespie ,c\nty47 ,9 we/ ,texas1 ame?y/ has be5 f\nd 9 ,c5ozoic igne\s rocks 9 ! ,si]ra ,blanca & ,quitman ,m\nta9s ( ,hudspe? ,c\nty & 9 ! ,alp9e area ( ,brew/] ,c\nty4 ,illu/ration3 ,milky qu>tz f ,burnet ,c\nty1 ,texas4 ,a v>iety ( qu>tz ) a milk-:ite color & a glassy to greasy lu/] is call$ milky qu>tz4 ,x occurs ei!r z cry/als or z cry/all9e masses4 ,v little light w pass ?r\gh x4 ,9 c5tral ,texas1 milky qu>tz occurs abundantly 9 ! ,precambrian rocks ( ! ,llano uplift area 9 ,blanco1 ,burnet1 ,gillespie1 ,llano1 & ,mason c\nties4 ,x also is f\nd 9 "s ( ! rocks ( ! ,trans-,pecos c\ntry ( we/ ,texas1 su* z 9 ! ,c>rizo ,m\nta9s ( ,culb]son & ,hudspe? c\nties4 ,o!r good places to look = ?is v>iety ( qu>tz are 9 ! s&s & gravels along _m /reams 9 ,texas4 ,"s qu>tz has a glassy to a greasy lu/] & a rose or p9k color4 ,rose qu>tz1 z ?is v>iety is call$1 commonly occurs z masses r ?an z individual cry/als4 ,x c be f\nd along "s ( ! /reams 9 ,texas & also 9 igne\s rocks1 su* z ^? ( ! ,llano uplift area ( c5tral ,texas4 ,a k9d ( qu>tz ) a smoky br[n1 a smoky yell[1 or a d>k br[ni%-black color is call$ smoky qu>tz4 ,its lu/] is glassy1 & x may be ei!r transluc5t or transp>5t4 ,smoky qu>tz is commonly f\nd z cry/als t are %ap$ l #f-sid$ prisms ) pyramid-l ends4 ,x is commonly associat$ ) igne\s rocks1 & beautiful specim5s h be5 f\nd 9 ! ,lake ,bu*anan area ( ,llano & ,burnet c\nties 9 c5tral ,texas4 ,illu/ration3 ,smoky-qu>tz cry/als f ,burnet ,c\nty1 ,texas4 ,a cryptocry/all9e v>iety ( qu>tz1 *alc$ony1 has a waxy to dull lu/] & a tan1 :ite1 gray1 or light-blue color4 ,x is transluc5t b n transp>5t4 ,*alc$ony does n h its own cry/al %ape b in/ead is f\nd 9 masses t l9e or fill cracks1 pores1 & o!r cavities 9 rocks4 ,x is =m$ :5 wat] conta9+ silicon sl[ly seeps into ^! op5+s 9 ! rocks & deposits ! silicon dioxide !re z *alc$ony4 ,*alc$ony commonly occurs 9 "s ( ! ,t]ti>y rocks ( ! ,gulf ,coa/al ,pla94 ,= example1 *alc$ony associat$ ) opal is f\nd ne> ,fre] 9 nor!rn ,duval ,c\nty4 ,9 ! ,high ,pla9s ( we/ ,texas1 x is f\nd 9 alkali-lake deposits1 su* z at ,%aft] ,lake 9 ,&rews ,c\nty & at ,c$> ,lake 9 ,ga9es ,c\nty4 ,9 ! ,trans-,pecos c\ntry ( we/ ,texas1 x c be f\nd fill+ small cavities 9 extrusive igne\s rocks4 ,illu/ration3 ,poli%$ agate f ,rio ,gr&e gravels ( ,zapata ,c\nty1 ,texas4 ,a v>iety ( *alc$ony t g5]ally is made up ( m ?an "o color is call$ agate 7al?\gh agates consi/+ ( sev]al %ades ( a s+le color are also f\nd74 ,! colors may be spread out unev5ly s t ! agate has a cl\dy appe>ance1 or !y c be arrang$ 9 wavy1 9 /raight1 or 9 conc5tric l9es or b&s4 ,if ! b&s are /raight & p>allel1 ! specim5 is call$ onyx4 ,agate t has a moss-l or tree-l design 9 x is call$ moss agate4 ,"s agates make attractive gem/ones :5 cut & poli%$4 ,illu/ration3 ,jasp] f ,uvalde ,c\nty1 ,texas4 ,d>k areas are br[ni% r$2 light areas are a yell[i%-tan4 ,mu* agate has be5 f\nd fill+ cavities 9 ,c5ozoic igne\s rocks 9 ,brew/]1 ,presidio1 & o!r c\nties 9 ! ,trans-,pecos c\ntry ( we/ ,texas4 ,x has be5 f\nd also 9 an area ab\t #aj to #ae miles wide along ! ,rio ,gr&e1 mo/ly 9 s\!rn ,webb ,c\nty & 9 ,zapata & ,/>r c\nties4 ,trees & o!r plants h be5 replac$ by agate4 ,_m specim5s ( agatiz$ wood h be5 collect$ f ,t]ti>y =mations 9 ,fayette1 ,gonzales1 ,lee1 ,wa%+ton1 & o!r c\nties ( ! ,gulf ,coa/al ,pla94 7,! agatiz$ wood1 along ) opaliz$ wood1 occurs )9 ab\t #bj miles ( ! b\nd>y betwe5 no4 #b & no4 #c on ! geologic map1 pp4 #d-e47 ,a h>d1 compact1 slightly transluc5t v>iety ( cryptocry/all9e qu>tz is call$ jasp]4 ,x commonly has a r$1 br[n1 or yell[ color due to ! pres5ce ( an iron oxide1 su* z hematite4 ,"s jasp] is made up ( irregul> b&s ( m ?an "o ( ^! colors4 ,?is v>iety ( qu>tz (t5 is poli%$ to make attractive gem or ornam5tal /ones4 ,x has be5 collect$ at sev]al localities 9 ,texas1 p>ticul>ly f creek & riv] gravels4 ,/>r & o!r ne>by c\nties along ! ,rio ,gr&e h furni%$ a numb] ( good specim5s4 ,a h>d1 smoo?1 compact1 transluc5t rock t is made up mo/ly ( cryptocry/all9e qu>tz is call$ *]t or fl9t4 ,x is :ite1 black1 or "s %ade ( gray1 br[n1 or p9k1 & its lu/] is waxy1 slightly glassy1 or dull4 ,*]t is f\nd 9 _m creek & riv] gravels 9 ,texas4 ,x also occurs ) lime/one1 su* z 9 ! ,l[] ,cretace\s ,edw>ds ,lime/one ( c5tral ,texas & 9 ! ,ordovician ,ell5burg] /rata 9 ! ,llano uplift area4 ,*]t also is f\nd ) ! ,ordovician rocks ( ! ,m>a?on area ( ,brew/] ,c\nty4 ,geologi/s d n agree on :e!r *]t & fl9t are two names = "o v>iety ( rock1 or :e!r ea* is a sep>ate v>iety4 ,"s1 h[ev]1 n[ give *]t a geological mean+ & fl9t an ar*aeological mean+4 ,!y use ! ^w *]t to describe geological =mations or rock specim5s4 ,!y give ! "n fl9t to ! same rock :5 x has be5 us$ by ,indians 9 mak+ arr[heads1 scrib]s1 scrap]s1 & spe>heads4 ,qu>tzite ,qu>tzite is ei!r a metamorphic rock or a s$im5t>y rock4 7,! s$im5t>y k9d ( qu>tzite is describ$ ) s& & s&/one on p4 #hf47 ,metamorphic qu>tzite is made up mo/ly ( qu>tz4 ,x =ms :5 heat & fluids bel[ ! e>?'s surface cause ! gra9s & cem5t ( a qu>tz s&/one to recry/allize4 ,:5 ?is happ5s1 ! gra9s int]lock & are no long] held toge!r by cem5t4 ,metamorphic qu>tzite1 l s$im5t>y qu>tzite1 is a h>d1 firm rock t breaks ?r\gh ! qu>tz gra9s in/ead ( betwe5 !m4 ,anci5t ,precambrian metamorphic qu>tzite occurs at ! surface 9 ! ,llano uplift area ( c5tral ,texas1 9 ! ,van ,horn area ( we/ ,texas1 & 9 ! ,frankl9 ,m\nta9s nor? ( ,el ,paso 9 extreme we/ ,texas4 ,rhyolite ,rhyolite is a f9e-gra9$ or glassy igne\s rock t commonly is extrusive or volcanic4 ,x has a p9k1 r$1 tan1 :ite1 gray1 purple1 or black color4 ,?is rock1 l granite1 is made up *iefly ( feldsp> & a silica m9]al1 su* z qu>tz1 b o!r m9]als may be pres5t4 ,bo? rhyolite & granite =m f ! same k9d ( molt5 rock mat]ial4 ,nev]!less1 ev5 ?\gh _! compositions are ! same1 ^! two rocks d n look alike4 ,_! textures diff] because granite =ms sl[ly & rhyolite =ms quickly4 ,mu* ( ! ,texas rhyolite =m$ f hot1 molt5 lava4 ,?is lava fl[$ out onto ! surface ei!r ?r\gh volcanic cones or cracks 9 ! gr\nd4 ,"s ( ! lava cool$ & h>d5$ too quickly = m9]al gra9s to develop4 ,?is rapidly cool$ lava =m$ a rhyolite rock t is made up1 at lea/ p>tly1 ( glass4 ,9 _m ( ! rhyolites1 cry/all9e m9]al gra9s 7 able to =m1 b ^! gra9s are extremely small1 & y may n be able to di/+ui% !m ev5 ) a magnify+ glass4 ,"s rhyolite1 because x h>d5$ f mov+1 fl[+ lava1 has /reaks & b&s ( diff]5t colors & textures4 ,?is rhyolite has fl[ /ructure4 ,"o v>iety ( rhyolite has easily se5 cry/als & gra9s ( m9]als1 su* z feldsp>1 qu>tz1 & mica1 scatt]$ ?r\gh a mass ( ! t9y cry/all9e gra9s 79 mu* ! same way t rais9s are scatt]$ ?r\gh a cake74 ,! easily se5 cry/als & gra9s are call$ ph5ocry/s1 & ! rock itself is call$ a rhyolite porphyry4 ,_m rhyolites & rhyolite porphyries occur 9 ! ,t]ti>y igne\s rocks ( ! ,trans-,pecos c\ntry ( we/ ,texas4 ,j a few ( ^! localities include ! ,b>rilla ,m\nta9s ( ,jeff ,davis & ,reeves c\nties1 ! ,*isos ,m\nta9s ( ,brew/] ,c\nty1 ! ,*9ati ,m\nta9s ( ,presidio ,c\nty1 & ! ,davis ,m\nta9s ( ,jeff ,davis ,c\nty4 ,rock ,cry/al4 ,see ,qu>tz4 ,rock ,gypsum4 ,see ,gypsum4 ,rock ,salt4 ,see ,halite4 ,rose ,qu>tz4 ,see ,qu>tz4 ,salt4 ,see ,halite4 ,s& & ,s&/one ,s& is a loose1 uncem5t$ s$im5t>y deposit made up ( fragm5ts ( wea!r$ rocks & m9]als4 ,^! fragm5ts mu/ be ( a c]ta9 size 7betwe5 _/ millimet] & #b millimet]s 9 diamet]7 9 ord] to be call$ s& gra9s4 ,! l>ge/ s& gra9s are ab\t ! size ( a p9head4 ,s& gra9s are small] ?an ! fragm5ts kn[n z granules2 !y are l>g] ?an ^? kn[n z silt4 ,_m s&s are made up *iefly ( gra9s ( qu>tz4 ,?is m9]al is pl5tiful & does n easily wea!r away4 ,9 addition1 rock fragm5ts & _m o!r m9]als1 su* z feldsp>1 mica1 gypsum1 magnetite1 & g>net1 are f\nd z s& gra9s4 ,ra9s wa% _m ( ! s& gra9s & o!r wea!r$ rock & m9]al fragm5ts into creeks & riv]s4 ,^! /reams may c>ry ! s& & o!r s$im5ts long di/ances be=e deposit+ !m4 ,today1 we f9d s&s along ! banks ( _m creeks & riv]s 9 ,texas & along ! bea*es ( ! ,gulf ( ,mexico4 ,! s& 9 ! riv]s is 9 transit to ! ,gulf4 ,9 addition1 s& occurs at ! surface 9 o!r ,c5ozoic =mations & 9 "s ( ! ,paleozoic & ,mesozoic =mations ( ,texas4 ,s& has _m uses4 ,mu* build+ s&1 :i* is us$ 9 mort> & concrete1 is produc$ f num]\s s& & gravel pits 9 ,texas4 ,pure qu>tz s& t c be us$ to make glass is kn[n z glass s&4 ,"s ( x is f\nd 9 nor?-c5tral ,texas 9 ,l[] ,cretace\s =mations4 ,a l>ge glass s& qu>ry is locat$ at ,santa ,anna 9 ,coleman ,c\nty4 ,along ! ,gulf ,coa/al ,pla91 s& t is us$ 9 glassmak+ occurs 9 ,eoc5e ,t]ti>y /rata4 ,a co>se-gra9$ s&1 bla/ s&1 is us$ ) compress$ air to clean ! walls ( brick & /one build+s & to c>ve designs on monum5t /ones1 su* z m>bles4 ,"s co>se s& is also us$ z a filt]+ s& 9 purify+ wat]4 ,^! types ( s& h be5 produc$ f ! ,gulf ,coa/al ,pla9 z well z f o!r areas ( ,texas4 ,s& gra9s1 :5 nature cem5ts !m toge!r1 make up ! s$im5t>y rock s&/one4 ,"s s&/ones =m :5 und]gr\nd wat] c>ry+ dissolv$ m9]al matt] moves ?r\gh loose s&4 ,z ! dissolv$ m9]al matt] comes out ( solution1 x =ms a cem5t t b9ds ! s& gra9s toge!r4 ,! cem5t may be mat]ial su* z calcite 7calcium c>bonate71 qu>tz1 *alc$ony1 or opal1 :i* are silica m9]als1 & limonite & hematite1 :i* are iron oxides4 ,clay also may s]ve z a cem5t4 ,x is ei!r deposit$ along ) ! s& or is =m$ f wea!r$ feldsp> s& gra9s4 ,! color ( ! cem5t+ mat]ial helps det]m9e ! color ( ! rock4 ,iron oxide cem5t1 = example1 causes ! s&/one to h a r$di%1 yell[i%1 or br[ni% color4 ,s&/ones also are :ite1 black1 gray1 gre51 or cream color$4 ,ord9>ily1 s&/ones break ?r\gh ! cem5t+ mat]ial1 n ?r\gh ! s& gra9s4 ,?us1 ! brok5 surface ( ! rock feels r\gh & gritty4 ,"s qu>tz s& gra9s1 h[ev]1 are tightly cem5t$ ) silica to =m an extremely h>d & compact rock4 ,if ?is rock breaks smoo?ly ?r\gh ! gra9s in/ead ( betwe5 !m1 x is kn[n z qu>tzite4 ,"s ( ?is s$im5t>y qu>tzite occurs 9 ! ,texas ,gulf ,coa/al ,pla9 9 ! ,t]ti>y ,catah\la /rata4 7,ano!r k9d ( qu>tzite is describ$ on pp4 #hd-he47 ,illu/ration3 ,s&/one f ! ,eoc5e ,wilcox ,gr\p ( /rata ( nor?we/]n ,zavala ,c\nty1 ,texas4 ,ord9>y s&/ones are se5 at ! surface 9 _m localities 9 ,texas1 & a numb] ( !m h be5 us$ z build+ /ones4 ,"s ( ! places :]e s&/ones occur are 9 ! ,cambrian & ,p5nsylvanian =mations ( ! ,llano uplift area ( c5tral ,texas & 9 ! ,p5nsylvanian1 ,p]mian1 & ,l[] ,cretace\s =mations ( nor?-c5tral ,texas4 ,t]ti>y s&/ones occur 9 ! ,texas ,gulf ,coa/al ,pla91 & ,triassic s&/ones are f\nd along ! edges ( ! ,texas ,high ,pla9s4 ,s&/one is also f\nd 9 _m =mations ( ! ,trans-,pecos c\ntry ( we/ ,texas4 ,s&/one4 ,see ,s& & ,s&/one4 ,sat9 ,sp>4 ,see ,gypsum4 ,s*i/ ,s*i/ is a metamorphic rock t splits easily along ?91 g5]ally p>allel lay]s1 call$ folia4 ,^! lay]s may be ei!r /raight or curv$1 & !y are made up ( cry/all9e gra9s ( "o or m ?an "o m9]al4 ,?is /ructure is call$ s*i/osity or foliation4 ,:5 y exam9e s*i/1 y w see t _m ( ! m9]al gra9s are flat or long1 & t !y are l9$ up 9 "o direction to =m ! lay]s4 ,"s s*i/s h fairly l>ge cry/als 7_m ) p]fect %apes7 scatt]$ ?r\gh !m4 ,= example1 mica s*i/s may conta9 beautiful cry/als ( g>net4 ,ea* k9d ( s*i/ is nam$ = an out/&+ m9]al t x conta9s4 ,mica s*i/ conta9s a l>ge am\nt ( mica4 ,we also f9d hornbl5de s*i/1 act9olite s*i/1 *lorite s*i/1 talc s*i/1 & graphite s*i/4 7,graphite s*i/ is discuss$ ) graphite on p4 #fc47 ,s*i/s =m f o!r rocks1 su* z granite1 gabbro1 or %ale4 ,! rocks are *ang$ into s*i/s by fluids & by heat & pressure bel[ ! e>?'s surface4 ,extremely anci5t s*i/s t =m$ dur+ ,precambrian "t are expos$ at ! surface 9 ! ,allamoore--,van ,horn area ( we/ ,texas & 9 ! ,llano uplift area ( c5tral ,texas4 ,geologi/s believe t ! ,packsaddle ,s*i/ ( ! ,llano uplift area 0 once %ale4 ,good exposures ( ?is s*i/ are se5 9 ! ,honey ,creek area ne> ,packsaddle ,m\nta9 9 ,llano ,c\nty4 ,s*orl4 ,see ,t\rmal9e4 ,s$im5t>y ,qu>tzite4 ,see ,s& & ,s&/one4 ,sel5ite4 ,see ,gypsum4 ,s]p5t9e ,s]p5t9e is ! "n giv5 bo? to a rock & to a m9]al4 ,! m9]al s]p5t9e 7a hydr\s magnesium silicate7 is f\nd 9 two diff]5t =ms4 ,if x is fibr\s1 x is call$ *rysotile2 if x is lay]$ & platy1 x is kn[n z antigorite4 ,antigorite is br[ni% gre5 & smoo? & waxy look+4 ,"s ( x c be split into ?9 %eets4 ,*rysotile is made up ( gre5i%1 silky fib]s1 :i* may be brittle & break ap>t 9 l>ge pieces4 ,if1 h[ev]1 ! fib]s c be pull$ ap>t into s(t flexible1 little ?reads1 ! m9]al is call$ *rysotile asbe/os4 ,light w pass ?r\gh bo? ^! v>ieties ( s]p5t9e1 & bo? are s(t en\gh to be scrat*$ by a pocket knife4 ,:5 rubb$ across a /reak plate1 !y leave :ite /reaks4 ,antigorite & *rysotile h no cry/al %apes ( _! own1 b sev]al o!r m9]als c alt] to =m ^! two v>ieties ( s]p5t9e4 ,?us antigorite & *rysotile may be f\nd z pseudomorphs 9 a cry/al %ape t orig9ally belong$ to ano!r m9]al4 ,antigorite & *rysotile are commonly f\nd closely mix$ ) dolomite1 talc1 magnetite1 calcite1 pyrite1 & sev]al o!r m9]als4 ,^! m9]als make up s]p5t9e rock 7also call$ s]p5t9ite74 ,?is rock ord9>ily is "s %ade ( gre5 7su* z :iti%1 yell[i%1 br[ni%1 blui%1 or d>k blacki% gre571 & x may be mottl$4 ,x is brittle or t\gh & g5]ally is massive4 ,s]p5t9e rock1 l ! s]p5t9e m9]als1 is fairly s(t--y c scrat* x ) a pocket knife4 ,9 ! ,llano uplift area ( c5tral ,texas1 s]p5t9e rock is f\nd among ,precambrian metamorphic rocks1 su* z gneiss & s*i/4 ,an especially l>ge deposit 9 ?is area is kn[n z ! ,coal ,creek s]p5t9e mass4 ,x is ov] #c miles long1 & at "o place1 x is almo/ #a miles wide4 ,?is mass ( s]p5t9e ext5ds across ! ,blanco-,gillespie ,c\nty l9e 9 ! extreme nor!rn p>ts ( ^! two c\nties4 7,a little fibr\s *rysotile is f\nd "h1 b x w n break into flexible en\gh ?reads to be call$ *rysotile asbe/os47 ,sev]al o!r deposits ( s]p5t9e occur 9 nor!a/]n ,gillespie ,c\nty & 9 s\!rn ,llano ,c\nty4 ,x is believ$ t ! ,coal ,creek s]p5t9e 0 =m$ f an igne\s rock su* z p]idotite1 :i* is made up *iefly ( gra9s ( ! m9]al oliv9e4 ,! p]idotite may h be5 alt]$ into s]p5t9e by und]gr\nd wat]s t seep$ ?r\gh x4 ,x is possible1 h[ev]1 t o!r s]p5t9es 9 ! area 7 =m$ :5 rocks 7 alt]$ by hot fluids & great pressures f> bel[ ! e>?'s surface4 ,! ,llano area s]p5t9e has be5 widely us$ 9 t]razzo floors4 ,to make ^! floors1 small pieces ( s]p5t9e & o!r color$ rocks are put into cem5t t is spread ov] a concrete slab4 ,!n1 aft] ! cem5t has h>d5$1 x is gr\nd to a flat1 smoo? surface & poli%$4 ,! result+ t]razzo floor is bo? colorful & durable4 ,s]p5t9e rock also is cut into slabs1 poli%$1 & us$ z indoor build+ /ones4 ,v]de antique1 a v>iety (t5 se5 9 ! lobbies ( (fice build+s1 consi/s ( gre5 s]p5t9e rock ) /reaks ( :ite calcite or dolomite 9 x4 ,9 ! ,balcones fault zone area 7%[n on ! ,texas physiographic outl9e map1 p4 #db7 f ,uvalde ,c\nty to ,williamson ,c\nty1 s]p5t9e occurs ) ,upp] ,cretace\s rocks4 ,! s]p5t9e rock is se5 at ! surface 9 a few places 7su* z 9 ,travis & ,uvalde c\nties71 b mu* ( x is und]gr\nd4 ,9 sev]al oil fields ( ?is area 7z at ,?rall field 9 ,williamson ,c\nty & at ,lytton ,spr+s field 9 ,caldwell ,c\nty71 ! s]p5t9e rocks conta9 oil4 ,s]p5t9ite4 ,see ,s]p5t9e4 ,%ale ,%ale is a s$im5t>y rock made up ( tightly pack$ clay & mud p>ticles4 ,x has a smoo? appe>ance because x is s f9e gra9$4 ,9 fact1 mo/ ( ! p>ticles 9 x are too small to be di/+ui%$ ) a magnify+ glass4 ,^! p>ticles are ! wea!r$ rema9s ( e>li] rocks4 ,!y 7 c>ri$ by creeks & riv]s to o!r p>ts ( ! l& or to ! sea1 :]e !y =m$ lay]s ( clay & mud4 ,lat]1 o!r s$im5ts 7 deposit$ on top ( !m4 ,! weight ( ^! new s$im5ts squeez$ ! clays & muds toge!r to =m firm1 compact %ale4 ,%ale looks v mu* l "s clays4 ,x1 l clay1 c be almo/ any color4 ,if ! %ale conta9s animal or plant matt]1 x is black1 gray1 or blue4 ,if x conta9s iron oxide 7_m m9]als conta9+ iron alt] to ?is mat]ial71 x is a %ade ( r$1 yell[1 or br[n4 ,%ale is s(t & c be easily scrat*$ by a knife4 ,x also is brittle & crumbles easily4 ,?is rock has a prop]ty t w help y to di/+ui% x f clay3 ! p>ticles t make up ! %ale 7 deposit$ 9 lay]s1 & ! %ale splits into flat1 ?9 flakes along ^! lay]s1 :i* clay w n d4 ,%ale is fairly abundant 9 ,texas1 especially 9 ,mississippian1 ,p5nsylvanian1 & ,cretace\s =mations4 ,= example1 ,p5nsylvanian %ales are f\nd at ! surface 9 nor?-c5tral ,texas1 9 ! area ar\nd ! ,llano uplift ( c5tral ,texas1 & 9 ! ,m>a?on & ,solit>io uplifts ( we/ ,texas4 ,_m ( %ale's uses are ! same z ^? ( clay4 ,"s ( x c be us$ to make brick1 tile1 & o!r products1 & "s is (t5 us$ in/ead ( clay 9 mak+ portl& cem5t4 ,cem5t plants at ,dallas1 ,el ,paso1 ,=t ,wor?1 & ,waco are locat$ at places :]e ,cretace\s lime/ones1 :i* also are us$ 9 cem5t mak+1 & ,cretace\s %ales are f\nd ne> ea* o!r at ! surface4 ,oil %ale1 f :i* petroleum c be obta9$ by heat+1 has be5 f\nd 9 c5tral ,texas4 ,x occurs 9 ,mississippian =mations 9 ,lampasas1 ,mc,culloch1 & ,san ,saba c\nties4 ,because oil is mu* less exp5sive to obta9 f wells1 x is n produc$ f ^! %ales4 ,silv] ,m9]als 7,arg5tite1 ,c]>gyrite1 ,native ,silv]7 ,silv] has _m uses4 ,l gold1 x is a beautiful metal t long has be5 us$ = co9s & ornam5ts4 ,a l>ge am\nt ( silv] goes to make articles su* z spoons1 =ks1 platt]s1 & trays4 ,! photographic indu/ry uses silv]--mu* ( ! film = cam]as is coat$ ) a silv] halide4 ,doctors & d5ti/s use silv]1 too4 ,! mixture t a d5ti/ uses to fill tee? conta9s silv] along ) sev]al o!r metals4 ,doctors sometimes use silv] wire to fa/5 brok5 bones1 & silv] comp\nds & solutions1 su* z silv] nitrate1 are us$ 9 "s k9ds ( m$ical treatm5t4 ,p]haps m p h he>d ( leg5d>y1 lo/ silv] m9es ( ,texas ?an ( ! actual & important silv] deposits f\nd 9 ! ,trans-,pecos c\ntry ( we/ ,texas4 ,"s ( ! we/ ,texas silv] m9]als include arg5tite1 c]>gyrite1 & native silv]4 ,al?\gh ! arg5tite & native silv] commonly f\nd !re are mix$ ) gal5a1 a lead m9]al1 or ) *alcocite1 a copp] m9]al1 !y also occur sep>ately4 ,! elem5t silv] is f\nd alone z native silv]4 ,:5 pure1 x is r easy to recognize4 ,x is metallic & has a silv]-:ite color t may t>ni% to gray1 black1 or yell[i% br[n4 ,native silv] is heavy 7x has a specific gravity ( #aj4e7 & s(t 7a pocket knife scrat*es x easily74 ,:5 y rub x across a /reak plate1 native silv]1 unless x is t>ni%$1 leaves a %9y1 silv]-:ite /reak4 ,?is metal is s ductile t x c be drawn into a wire4 ,x is also malleable & flatt5s :5 hit ) a hamm]4 ,silv] occurs z cry/als1 :i* are poorly %ap$ cubes & octah$rons1 or z irregul> masses4 ,x may h a net-l appe>ance 7call$ reticulate71 or x may be %ap$ l little ne$les 7describ$ !n z acicul>74 ,x occurs 9 wires 7!n call$ fili=m7 or z scales or plates4 ,illu/ration3 ,prospector4 ,two ( ! ,texas silv] m9]als1 arg5tite & c]>gyrite1 d n resemble silv] at all4 ,arg5tite1 a silv] sulfide1 is also call$ silv] glance4 ,x is a d>k1 lead-gray m9]al ) a metallic lu/] t wea!rs to a dull black4 ,:5 y rub x across a /reak plate1 arg5tite gives a %9y1 blacki% to lead-gray /reak4 ,?is m9]al is s(t en\gh to leave a m>k on pap]4 ,x has a specific gravity ( #g4c1 & x is sectile en\gh to be cut smoo?ly 7l soap7 ) a knife4 ,9 "s places arg5tite is f\nd z irregul> masses or z a coat+ on rocks & o!r m9]als4 ,ano!r silv] m9]al1 c]>gyrite 7or horn silv]7 is a silv] *loride4 ,?is m9]al has a nonmetallic lu/] & is transp>5t to transluc5t4 ,x resembles pe>l-gray1 :ite1 gre5i%1 or colorless wax4 ,:5 expos$ to ! light x turns violet br[n or black4 ,c]>gyrite is s(t--y c scrat* x ) a f+]nail4 ,l arg5tite1 x is sectile4 ,?is m9]al has a specific gravity ( #e4e1 & x commonly occurs z irregul> masses & z cru/s4 ,^! silv] m9]als h be5 m9$ at a numb] ( places 9 ,trans-,pecos ,texas4 ,! l>ge/ silv] m9e 9 ,texas1 ! ,presidio m9e1 is locat$ ne> ,%aft] 9 s\?-c5tral ,presidio ,c\nty4 ,x conta9s arg5tite1 c]>gyrite1 & native silv]1 along ) gal5a & sev]al o!r m9]als4 ,?is m9e is n op5 n[1 b 9 ! ye>s betwe5 #ahhe & #aidb1 x produc$ a l>ge am\nt ( silv] along ) "s lead & gold4 ,!re are sev]al o!r lead-silv] m9es 9 ?is ,%aft] area1 b none has produc$ z mu* z ! ,presidio m9e4 ,9 ?is m9e1 ! silv] m9]als occur mo/ly 9 l>ge1 flat deposits 9 ,p]mian lime/one & o!r s$im5t>y rocks4 ,! m9]als are believ$ to h be5 deposit$ !re--probably dur+ ,t]ti>y "t--by solutions t came f hot magma f> bel[ ! rocks4 ,z !y mov$ 9 along ! lay]s ( lime/one1 ! solutions replac$ portions ( ?is rock ) m9]als conta9+ silv]1 lead1 & o!r elem5ts4 ,lat]1 wat] seep$ into ^! deposits & dissolv$ "s ( ! m9]als4 ,?is dissolv$ mat]ial 0 !n re-deposit$1 & x =m$ mo/ ( ! m9]als we n[ f9d !re4 ,no silv] is be+ m9$ 9 ,texas at pres5t1 b x has1 9 ! pa/1 be5 produc$ f o!r ,trans-,pecos m9es4 ,gal5a t conta9s silv] 7call$ arg5tif]\s gal5a7 has be5 m9$ at ! ,bird m9e at ,altuda ,m\nta9 7ab\t #ad miles ea/ ( ,alp9e7 9 nor!rn ,brew/] ,c\nty4 ,x also has be5 obta9$ f m9es 9 ! ,quitman ,m\nta9s & 9 ! ,eagle ,m\nta9s ( ,hudspe? ,c\nty4 ,"s c]>gyrite has be5 m9$ at ! ,plata ,v]de m9e ne> ! ,culb]son-,hudspe? ,c\nty l9e4 ,sev]al m9es 9 ! ,van ,horn area ( ,culb]son & ,hudspe? c\nties h produc$ silv] along ) copp]4 ,an important silv] m9e 9 ?is area is ! n[ idle & flood$ ,hazel m9e4 7,?is m9e is describ$ ) copp] m9]als on p4 #eb47 ,smoky ,qu>tz4 ,see ,qu>tz4 ,soap/one4 ,see ,talc & ,soap/one4 ,specul> ,hematite4 ,see ,hematite4 ,sulfur ,sulfur is "o ( ,texas' mo/ valuable m9]als4 ,x consi/s ( only a s+le elem5t1 sulfur4 ,?is m9]al has a res9\s lu/] & is transp>5t to transluc5t4 ,sulfur ord9>ily is yell[1 b impurities cause x to look gre5i%1 br[ni%1 r$di%1 or grayi%4 ,:5 y rub x across a /reak plate1 x leaves a :ite or a pale-yell[ /reak4 ,sulfur has a specific gravity ( #b4jd to #b4ji & is s(t en\gh to be scrat*$ by a copp] p5ny4 ,x breaks ) a con*oidal to unev5 fracture4 ,:5 x gets hot en\gh 7#dgh ,fahr5heit71 sulfur w burn4 ,= ?is reason1 x (t5 is call$ brim/one4 ,sulfur does n conduct electricity & is a poor conductor ( heat4 ,y c te/ h[ poorly heat passes ?r\gh x by hold+ a fragm5t ( sulfur up to y\r e>4 ,y may be able to he> a crackl+ s\nd4 ,! s\nd results :5 ! out] "p ( ! fragm5t exp&s 7due to ! heat f y\r h&7 :ile ! inn] "p 7:i* has receiv$ no heat7 rema9s un*ang$4 ,cry/als ( sulfur are sometimes f\nd1 & mo/ ( !m h ei!r a d\ble-pyramid %ape or a flat1 tabul> %ape4 ,sulfur also occurs z compact masses1 z cru/s1 & z scatt]$ gra9s4 ,native sulfur deposits are f\nd 9 two widely sep>at$ areas ( ,texas--"o 9 we/ ,texas & ! o!r along ! ,gulf ,coa/ 9 s\!a/ ,texas1 ext5d+ ov] into ,l\isiana4 ,9 ! ,gulf ,coa/ area1 native sulfur is f\nd on "s ( ! salt domes4 ,! salt domes are huge 7f ab\t half a mile to m ?an #b miles across71 column-%ap$ masses made up ( halite & "s anhydrite4 ,^! masses h pu%$ up t[>d ! surface ?r\gh ?\s&s ( feet ( s&1 clay1 & o!r s$im5t>y rocks4 ,on top ( _m ( ! salt columns is a cov]+ ( lime/one 7calcite71 anhydrite1 & gypsum kn[n z ! cap-rock4 ,x is 9 ?is cap-rock t ! sulfur is f\nd4 ,x is ?\ght t :5 ! masses ( halite & anhydrite pu%$ t[>d ! e>?'s surface1 "s ( ! upp] "p ( ! halite dissolv$4 ,! anhydrite1 h[ev]1 did n dissolve1 & x rema9$ on top ( ! salt column4 ,!n1 a "p ( ?is anhydrite 0 alt]$ into ! gypsum1 lime/one1 & sulfur t n[ are f\nd 9 "s ( ! cap-rocks4 ,laboratory exp]im5ts h %[n t ! sulfur 9 ! cap-rocks likely =m$ ?r\gh ! action ( sulfate-r$uc+ bact]ia4 ,^! bact]ia1 9 ! pres5ce ( petroleum1 conv]t$ ! sulfate 9 "s ( ! anhydrite into hydrog5 sulfide4 ,lat]1 hydrog5 sulfide 0 oxidiz$--p]haps by reaction ) m ( ! anhydrite--to =m ! sulfur4 ,mo/ ( ! l>ge cap-rock sulfur deposits are ab\t #a1ejj to #b1djj feet und]gr\nd4 ,at fir/1 an attempt 0 made to get ?is sulfur out ( ! gr\nd by digg+ %afts d[n to x1 b loose1 wet1 cav+ s&s & poison\s gases1 su* z hydrog5 sulfide1 made ?is m9+ me?od almo/ impossible4 ,f9ally1 a *emi/1 ,h]man ,fras*1 f\nd a way to obta9 ! sulfur by mak+ use ( sulfur's l[ melt+ po9t4 ,:5 sulfur gets slightly hott] ?an boil+ wat] 7#bce to #bdg ,fahr5heit71 x melts & becomes a d>k1 yell[i%-br[n liquid4 ,9 ! ,fras* me?od ( sulfur m9+1 a well is drill$ into ! salt-dome cap-rock1 & ?ree pipes1 "o inside ! o!r1 are put into ! well4 ,sup]heat$ wat] "u pressure 7hott] ?an #bab ,fahr5heit1 ! temp]ature at :i* wat] ord9>ily turns into /eam7 is s5t d[n "o ( ! pipes to melt ! sulfur 9 ! cap-rock ar\nd ! bottom ( ! well4 ,!n1 compress$ air is s5t d[n ano!r ( ! pipes4 ,?is air presses aga9/ ! liquid sulfur & =ces x up to ! surface ?r\gh ! ?ird pipe4 ,at ! surface1 ! sulfur is p\r$ into b9s1 :]e x cools & becomes a solid aga91 or x is transport$ molt51 9 pipel9es & tank]s4 ,sulfur has be5 obta9$ f a numb] ( ! ,texas ,gulf ,coa/ salt domes includ+ ,bryan ,m\nd1 ,clem5s dome1 ,damon ,m\nd1 & ,hosk9s ,m\nd 9 ,brazoria ,c\nty2 ,palangana dome 9 ,duval ,c\nty2 ,long ,po9t dome1 ,na% dome1 & ,or*>d dome 9 ,=t ,b5d ,c\nty2 ,high ,isl& dome 9 ,galve/on ,c\nty2 ,fannett dome & ,sp9dletop dome 9 ,jeff]son ,c\nty2 ,moss ,bluff dome 9 ,lib]ty ,c\nty2 ,gulf dome 9 ,matagorda ,c\nty2 & ,bol+ dome 9 ,:>ton ,c\nty4 ,9 we/ ,texas1 sulfur occurs 9 ,p]mian rocks bo? at ! surface & und]gr\nd4 ,a small am\nt ( sulfur has be5 m9$ 9 ! ,ru/l] ,spr+s area ( nor!a/]n ,culb]son ,c\nty & nor?we/]n ,reeves ,c\nty1 ab\t #ej miles nor?we/ ( ,pecos4 ,!re1 scatt]$ gra9s1 cry/als1 & irregul> masses ( sulfur occur 9 cracks & 9 dissolv$-out op5+s 9 ! ,ca/ile ,gypsum & 9 ! surface gravel1 gypsum1 s&1 & clay t cov] mo/ ( ?is =mation4 ,sulfur has _m uses4 ,x is us$ z an insect-kill]1 ?us help+ our food crops to gr[4 ,x is us$ 9 pulp & pap] manufactur+ & 9 ! vulcaniz+ ( rubb]4 ,"s o!r uses are 9 ! mak+ ( pa9ts1 dyes1 & explosives4 ,a l>ge am\nt ( sulfur goes to make sulfuric acid1 :i* itself has num]\s uses 9 ! *emical1 /eel1 oil ref9+1 & o!r indu/ries4 ,illu/ration3 ,sulfur is obta9$ f ! cap-rock ( ,gulf ,coa/al ,pla9 salt domes by ! ,fras* process4 ,sulfur ,uncem5t$ ,s$im5ts ,lime/one ,sulfur-,be>+ ,lime/one ,hot ,wat] ,melt$ ,sulfur ,anhydrite ,talc & ,soap/one ,talc1 a hydr\s magnesium silicate1 is an extremely s(t m9]al--y\r f+]nail scrat*es x easily4 ,x has a greasy or a pe>ly lu/]1 & its color is :ite1 light gre51 or gray4 ,:5 rubb$ across a /reak plate1 x leaves a :ite /reak4 ,talc cleaves p]fectly 9 "o direction1 & ! cleavage fragm5ts are ?91 flat1 & %eet-l4 ,its fracture is unev54 ,?is m9]al has a soaplike or greasy feel1 & x is sectile--a knife w cut ?r\gh x4 ,talc is n p>ticul>ly heavy--x has a specific gravity ( #b4g to #b4h4 ,?is m9]al seldom occurs ) a cry/al %ape4 ,m commonly x is massive & is granul> or lay]$4 ,talc is n always f\nd z a s+le1 pure m9]al4 ,9 nature1 x commonly occurs mix$ ) "o or m o!r m9]als1 su* z tremolite1 an?ophyllite1 *lorite1 & magnetite4 ,?is comb9ation ( talc ) o!r m9]als =ms a s(t1 greasy or soapy-feel+ metamorphic rock call$ soap/one4 ,! talc 9 ?is rock may be difficult to id5tify )\t special laboratory te/s4 ,9 ,texas1 talc & soap/one are f\nd 9 ,precambrian metamorphic rocks4 ,9 we/ ,texas1 talc occurs 9 an area ab\t #bj miles long 7j nor? ( ,u4 ,s4 ,highway #hj 9 ! vic9ity ( ,allamoore1 ,eagle ,flat sid+1 & ,talc ,rock sid+7 9 ,hudspe? ,c\nty4 ,"s ( ?is talc is m9$ f op5 pits & us$ by ! c]amic indu/ry to make wall tile4 ,"s ( x is f9ely gr\nd1 mix$ ) insect poison1 & us$ z insect p[d]s & du/s4 ,illu/ration3 ,talc s*i/ f ! ,allamoore area ( ,hudspe? ,c\nty1 ,texas4 ,deposits ( soap/one1 conta9+ talc1 occur 9 ! ,llano uplift area ( c5tral ,texas ) s*i/1 gneiss1 & s]p5t9e rocks 9 nor!a/]n ,gillespie1 nor?we/]n ,blanco1 & s\!rn ,llano c\nties4 ,small] deposits occur 9 nor!a/]n ,mason ,c\nty & 9 nor?we/]n & s\!a/]n ,llano ,c\nty4 ,! ,llano uplift area soap/ones are light gre5 to light buff4 ,x is ?\ght t "s ( !m 7 once igne\s rocks t conta9$ magnesium m9]als4 ,fluids1 along ) great heat & pressures bel[ ! e>?'s surface1 *ang$ ^! igne\s rocks into soap/one4 ,"s ( ?is ,llano uplift area soap/one is m9$ f op5 pits ne> ,will[ ,city 9 ,gillespie ,c\nty4 ,x is us$ mo/ly 9 mak+ insect p[d]s & ro(+ granules4 ,9 addition1 "s ( ! c5tral ,texas soap/ones h be5 us$ = he>?s & = fireplace l9+s4 ,topaz ,topaz1 an alum9um fluorosilicate1 is a m9]al especially priz$ by collectors because _m specim5s are gem/ones4 ,topaz is transp>5t1 has a glassy lu/]1 & is q h>d 7nei!r qu>tz nor a /eel file w scrat* x74 ,! topaz t has be5 f\nd 9 ,texas is ei!r colorless1 pale blue1 or sky blue4 ,?is m9]al is fairly heavy--its specific gravity is #c4d to #c4f4 ,x cleaves p]fectly 9 "o direction 7call$ basal cleavage71 & "s ( ! cleavage fragm5ts h a flat1 slabby appe>ance4 ,topaz is commonly f\nd z prism-%ap$ cry/als1 z cleavage fragm5ts1 & z irregul> gra9s4 ,"s fragm5ts ( topaz look l qu>tz4 ,topaz1 h[ev]1 is h>d] & heavi] ?an qu>tz1 & x has p]fect basal cleavage1 :i* qu>tz does n h4 ,9 ,texas1 cry/als1 gra9s1 & cleavage fragm5ts ( topaz occur 9 ! ,llano uplift area ( c5tral ,texas4 ,!y are f\nd ne> ,/reet] & ,grit 9 we/-c5tral ,mason ,c\nty & ne> ,katemcy 9 nor!rn ,mason ,c\nty4 ,"h1 "s ( ! topaz occurs 9 ,precambrian pegmatite ve9s t cut ?r\gh granite rocks4 ,mo/ ( ! topaz1 h[ev]1 is f\nd z pebbles 9 ! gravels ( ne>by creeks1 :]e x has wa%$ aft] wea!r+ out ( ! rocks4 ,illu/ration3 ,topaz cry/al f ne> ,/reet]1 ,mason ,c\nty1 ,texas4 ,topaz probably orig9ates :5 hot fluids move up out ( molt5 magma into cracks & cavities 9 ! surr\nd+ rocks4 ,!re1 ! fluids react ) elem5ts 9 ! rocks to =m ! topaz4 ,topaz is a good gem/one because1 9 addition to its beauty1 x is h>d & is n easily m>r$ by scrat*es4 ,! ,mason ,c\nty topaz makes excell5t gem/ones4 ,mo/ ( x is beautiful & cle> & is ei!r colorless or ( a pleas+ blue color4 ,^! /ones are cut1 poli%$1 & m\nt$ 9 r+s & o!r jewelry4 ,a numb] ( specim5s ( ?is ,mason ,c\nty topaz are display$ 9 museums4 ,t\rmal9e ,t\rmal9e is a complex silicate ( boron & alum9um4 ,o!r elem5ts1 su* z magnesium1 sodium1 li?ium1 calcium1 iron1 or fluor9e1 also may be pres5t4 ,?is m9]al has a glassy to res9\s lu/]4 ,only ! d>k-color$ v>ieties ( t\rmal9e h be5 f\nd 9 ,texas4 ,"o is a black v>iety call$ s*orl1 & ano!r is a br[n v>iety call$ dravite4 ,o!r k9ds ( t\rmal9e1 al?\gh n f\nd 9 ,texas1 are colorless or "s %ade ( blue1 yell[1 r$1 p9k1 or gre54 ,"s cry/als ev5 %[ m ?an "o color4 ,t\rmal9e is too h>d to scrat* ) a /eel file1 x has a specific gravity ( #c to #c4be1 & x has a con*oidal to unev5 fracture4 ,v little light passes ?r\gh ! d>k v>ieties1 & "s fragm5ts ( s*orl look l %9y1 black coal4 ,t\rmal9e occurs z masses )\t cry/al %apes1 b cry/als are commonly f\nd4 ,! cry/als are prism-%ap$ & h small v]tical grooves1 call$ /riations1 on ! prism faces4 ,:5 y look at "s cry/als f an end1 y w see t ! cross section is a triangle ) ! sides b[$ outw>d4 ,illu/ration3 ,black t\rmal9e cry/als ) milky qu>tz f nor? ( ,llano1 ,llano ,c\nty1 ,texas4 ,bo? ! black & ! br[n v>ieties ( t\rmal9e h be5 f\nd at sev]al places 9 ! ,llano uplift ( c5tral ,texas4 ,"o well-kn[n locality is at ,t[n ,m\nta9 nor? ( ,llano 9 ,llano ,c\nty4 ,"h1 ! t\rmal9e occurs 9 milky qu>tz t is associat$ ) ,precambrian granite rocks4 ,9 we/ ,texas1 9 ,culb]son & ,hudspe? c\nties1 black t\rmal9e occurs 9 pegmatite rocks 9 ! ,van ,horn ,m\nta9s1 ! ,c>rizo ,m\nta9s1 & ! ,wylie ,m\nta9s4 ,9 ! ,eagle ,m\nta9s ( ,hudspe? ,c\nty1 x is f\nd 9 metamorphic rocks z well z 9 pegmatites4 ,"s t\rmal9e =m$ f hot fluids conta9+ boron t 7 giv5 (f by magmas f> bel[ ! e>?'s surface4 ,^! fluids travel$ up ?r\gh cracks & o!r op5+s 9 ov]ly+ rocks4 ,z ! fluids react$ ) o!r elem5ts & comp\nds1 ! t\rmal9e =m$4 ,! cle>1 light-color$ v>ieties ( t\rmal9e are mu* admir$1 & !y are m widely us$ z gem/ones ?an are ! d>k-color$ v>ieties4 ,"s collectors1 h[ev]1 f9d t ! d>k-color$ ,texas t\rmal9es1 :5 cut & poli%$1 make %9y1 attractive gem/ones4 ,"s t\rmal9e is us$ z gr9d+ mat]ial1 b no ,texas t\rmal9e is produc$ = ?is purpose4 ,trav]t9e4 ,see ,calcite4 ,uranium ,m9]als 7,c>notite1 ,uranophane1 ,pit*bl5de7 ,9 #aide1 ! _w sudd5ly became aw>e ( ! awesome p[] ( atomic en]gy :5 ! elem5t uranium 0 us$ to produce "s ( ! fir/ atomic bombs4 ,uranium does n occur alone 9 nature b is f\nd comb9$ ) o!r elem5ts 9 a numb] ( m9]als4 ,all ( ! uranium m9]als are radioactive4 ,! uranium !y conta9 is gradually break+ d[n & *ang+ into a s]ies ( #ac o!r elem5ts1 call$ daught] elem5ts4 ,ea* daught] elem5t breaks d[n & *anges into ! next daught] elem5t ( ! s]ies4 ,:ile break+ d[n1 ^! elem5ts give (f p>ticles & rays ( en]gy4 ,?is en]gy or radioactivity is made up ( :at are call$ alpha p>ticles1 beta p>ticles1 & gamma rays4 ,y _c see1 he>1 ta/e1 smell1 or feel !m4 ,! alpha & beta p>ticles are weak & d n travel f>4 ,! gamma rays1 h[ev]1 c travel f>!r & c pass ?r\gh seem+ly solid mat]ial4 ,sci5ti/s h f\nd t ^! rays c move ?r\gh ab\t #a foot ( rock1 #b feet ( wat]1 & sev]al hundr$ feet ( air4 ,prospectors se>*+ = uranium m9]als c>ry in/rum5ts t are able to detect ?is radioactivity4 ,! uranium itself gives (f only alpha p>ticles1 b "s ( its daught] elem5ts give (f gamma rays4 ,^! daught] elem5ts are normally f\nd ) ! uranium1 & x is _! /rong gamma rays t ! in/rum5ts are mo/ apt to detect4 ,illu/ration3 ,a ,geig] c\nt] is us$ to detect radioactivity4 ,"o ( ! in/rum5ts us$ is ! ,geig] c\nt]4 ,x indicates radioactivity by means ( a met]1 a fla%+ light1 or a click+ s\nd1 :i* c be he>d ?r\gh e>phones4 ,ano!r in/rum5t = detect+ radioactivity is ! sc9tillation c\nt]4 ,x is m s5sitive ?an ! ,geig] c\nt] & x c detect radioactivity f a great] di/ance4 ,! sc9tillation c\nt] c be us$ f an automobile or an airplane1 b ! ,geig] c\nt] mu/ be q close to ! s\rce ( radioactivity to be ( use4 ,v>i\s uranium m9]als h be5 f\nd1 mo/ly 9 small am\nts1 9 a numb] ( places 9 ,texas4 ,"s ( ^! m9]als1 su* z uran9ite or pit*bl5de1 are heavy & d>k color$4 ,o!rs1 includ+ c>notite1 tyuyamunite1 autunite1 & uranophane1 are a %ade ( yell[ or gre54 ,!y are q s(t4 ,deposits ( ! light-color$ uranium m9]als h be5 m9$ f two areas ( ,texas4 ,"o ( ^! areas is 9 ,g>za ,c\nty on ! ,texas ,high ,pla9s1 & ! o!r is 9 ,k>nes & ,live ,oak c\nties 9 ! ,gulf ,coa/al ,pla94 ,"o ( ! light-color$ uranium m9]als1 c>notite1 is a potassium-uranium vanadate1 :i* has a bright can>y-yell[ or lemon-yell[ color4 ,?is m9]al is transp>5t to transluc5t & has an e>?y or a pe>ly lu/]4 ,c>notite usually is f\nd z cru/s & z p[d]y masses4 ,x is q s(t & c be scrat*$ ) a f+]nail4 ,c>notite1 along ) tyuyamunite1 autunite1 & sev]al o!r s(t1 yell[i% or gre5i% uranium m9]als1 is f\nd 9 ! ,texas ,gulf ,coa/al ,pla94 ,^! m9]als occur 9 ! ,jackson1 ,catah\la1 & ,oakville /rata 7:i* are ,t]ti>y 9 age7 9 an area ext5d+ f ,gonzales ,c\nty to ! ,rio ,gr&e 79 p>ts ( ! area indicat$ by no4 #b & no4 #c on ! geologic map1 pp4 #d-e74 ,! l>ge/ deposits 9 ?is di/rict h be5 f\nd 9 ! ,k>nes ,c\nty area4 ,! ,gulf ,coa/al ,pla9 uranium m9]als occur mo/ly ) s&/ones & clays 9 a sequ5ce ( /rata t conta9s volcanic a%4 ,x is believ$ t small scatt]$ am\nts ( uranium comp\nds t 7 pres5t 9 ! volcanic a% s$im5ts 7 dissolv$ by seep+ und]gr\nd wat]4 ,^! wat]s !n mov$ into ! s&/ones & clays :]e !y deposit$ ! uranium z c>notite & z o!r uranium m9]als4 ,ano!r uranium m9]al1 uranophane 7calcium-uranium silicate71 also occurs 9 ,texas4 ,uranophane has a yell[ to yell[-orange color & a pe>ly to greasy lu/]4 ,:5 rubb$ across a /reak plate1 x leaves a light yell[ to a light yell[-orange /reak4 ,x is s(t en\gh to be scrat*$ by a copp] p5ny4 ,uranophane has be5 f\nd 9 extrusive igne\s rocks 9 nor?we/]n ,presidio ,c\nty 9 we/ ,texas4 ,a d>k-color$ uranium m9]al1 pit*bl5de1 is a v>iety ( ! m9]al uran9ite1 uranium dioxide4 ,pit*bl5de does n occur ) a cry/al %ape b r z r\nd$ & irregul>-%ap$ masses4 ,x is br[ni% black1 gre5i% black1 or black4 ,if y rub x across a /reak plate1 pit*bl5de leaves a br[ni%-black /reak4 ,?is m9]al is heavy 7x has a specific gravity ( #f4e to #h4e7 & h>d 7a pocket knife w n scrat* x1 al?\gh a /eel file w74 ,pit*bl5de has a submetallic lu/] & looks dull1 greasy1 or l pit* or t>4 ,small am\nts ( pit*bl5de h be5 f\nd at sev]al places 9 ,texas4 ,"o ( ^! localities is a few miles we/ ( ,burnet 9 ,burnet ,c\nty 9 c5tral ,texas4 ,"h1 ! pit*bl5de occurs 9 ,precambrian igne\s rocks t are associat$ ) gneiss4 ,9 s\? ,texas1 "s f9e1 scatt]$ p>ticles ( pit*bl5de h be5 f\nd ab\t #cbe feet bel[ ! surface 9 ,t]ti>y 7,plioc5e7 s$im5ts t cov] ! ,palangana salt dome 9 ,duval ,c\nty4 ,no pit*bl5de is m9$ 9 ,texas4 ,uranophane4 ,see ,uranium ,m9]als4 ,vitrophyre4 ,see ,obsidian & ,vitrophyre4 ,volcanic ,a% 7,pumicite7 ,volcanic a% deposits1 :i* also are kn[n z pumicite1 are loose & p[d]y4 ,!y are made up mo/ly ( mat]ial t is ?r[n into ! air :5 volcanoes erupt4 ,if a volcano erupts ) a viol5t explosion1 ! ne>by rocks are bl[n into p[d]4 ,molt5 lava also is hurl$ into ! air1 :]e "s ( x imm$iately cools to become t9y bubbles & p>ticles ( glass4 ,! w9ds may c>ry "s ( ?is f9e mat]ial f> away be=e deposit+ x4 ,deposits ( volcanic a% are :ite1 blui%1 gre5i%1 yell[i%1 or grayi%1 & "s ( !m gli/5 l sn[ 9 ! sunlight4 ,!y feel r\gh & gritty4 ,:5 exam9$ "u a microscope1 ?is mat]ial %[s ! t9y curv$ & %>p-corn]$ p>ticles ( ! brok5 volcanic glass4 ,deposits ( volcanic a% may also conta9 clay1 silt1 s&1 or o!r impurities4 ,volcanoes1 :i* may h be5 locat$ 9 ! ,davis ,m\nta9s & 9 o!r areas ( we/ ,texas & 9 nor!rn ,mexico1 erupt$ dur+ ,t]ti>y "t4 ,! volcanic a% t we f9d at ! surface today 9 "s ( ! ,t]ti>y =mations 9 ,texas c\ld h come f ^! volcanoes4 ,t]ti>y volcanic a% deposits occur 9 ! ,texas ,gulf ,coa/al ,pla9 7su* z 9 ,brazos1 ,fayette1 ,k>nes1 ,polk1 ,/>r1 ,tr9ity1 & o!r c\nties7 & 9 ! ,trans-,pecos c\ntry ( we/ ,texas4 ,volcanic a% deposits ( ,quat]n>y 7,plei/oc5e7 age1 :i* are less ?an a million ye>s old1 are f\nd 9 a numb] ( c\nties on ! ,texas ,high ,pla9s4 ,f>!r to ! ea/1 a% deposits occur 9 ,baylor1 ,dick5s1 ,k5t1 & ,wilb>g] c\nties4 ,?is volcanic a% may h come f a volcano t erupt$ 9 nor!rn ,new ,mexico dur+ ,quat]n>y "t4 ,volcanic a% or pumicite has sev]al comm]cial uses4 ,"s is us$ to make pozzolan cem5t1 & "s is us$ 9 sweep+ comp\nds1 cleans+ & sc\r+ p[d]s1 & abrasive soaps4 ,pumicite has be5 m9$ 9 ,dick5s1 ,scurry1 ,/>r1 & sev]al o!r c\nties ( ,texas4 ,wad4 ,see ,manganese ,m9]als4 ,wood ,opal4 ,see ,opal4 ,,composition1 ,,h>dness1 ,,& ,,specific ,,gravity ,,( ,,"s ,,texas ,,m9]als ,= conv5i5t ref]5ce1 ! ,texas m9]als describ$ 9 ?is book are li/$ bel[1 toge!r ) _! *emical compositions1 specific gravities1 & h>dness4 ,y w be able to f9d simil> in=mation ab\t additional m9]als 9 m9]alogy textbooks su* z ^? not$ on page #bd4 ,m9]al ,composition ,specific ,gravity ,h>dness ,albite ,na,al,si,o #b4fb #f ,alm&ite ,fe,al 7,si,o7 #d4b #g ,amphibole ,ca,mg,si,o7,,oh7 #c4j-c4c #a-b asbe/os ,anhydrite ,ca,s,o #b4i #c-c ,arg5tite ,ag,s #g4c #b-b ,azurite ,cu7,,co77,,oh7 #c4gg #c-d ,b>ite ,ba,s,o #d4e #c-c ,biotite ,k7,mg1 #b4h-c4b #b-c ,fe7,al,si,o7,,oh7 ,braunite #c,mn,mn,o,mn,si,o #d4ge-d4hb #f-f ,calcite ,ca,c,o #b4gb #c ,c>notite ,k,o#b,,uo,v,on,h,o #e4jc #b ,cassit]ite ,sn,o #f4h-g4a #f-g ,cele/ite ,sr,s,o #c4ie-c4ig #c-c ,c]>gyrite ,ag,cl #e4e #a-a ,*alcocite ,cu,s #e4e-e4h #b-c ,*alcopyrite ,cu,fe,s #d4a-d4c #c-d ,c9nab> ,hg,s #h4aj #b ,dolomite ,ca,mg7,,co7 #b4he #c-d ,feldsp> 7see ,albite1 ,microcl9e1 ,or?oclase7 ,fluorite ,ca,f #c4ah #d ,gal5a ,pb,s #g4d-g4f #b ,g>net 7see ,alm&ite1 ,grossul>ite7 ,gold ,au #ae4j-ai4c #b-c ,graphite ,c #b4b #a-b ,grossul>ite ,ca,al7,si,o7 #c4ec #f ,gypsum ,ca,s,o#b;,h,o #b4cb #b ,halite ,na,cl #b4af #b ,hematite ,fe,o #e4bf #a-f ,holl&ite ,mn,ba,mn,o #d4g-e #d-f ,limonite ,fe,o7,,oh7n,h,o #c4f-d4j #a-e ,magnetite ,fe,o #e4ah #f ,mala*ite ,cu,,co7,,oh7 #c4i-d4jc #c-d ,mica 7see ,muscovite1 ,biotite7 ,microcl9e ,k,al,si,o #b4ed-b4eg #f ,muscovite ,k,al,si,o7,,oh7 #b4gf-c4a #b-b ,opal ,si,on,h,o #a4i-b4b #e-f ,or?oclase ,k,al,si,o #b4eg #f ,pit*bl5de ,,uo #f4e-h4e #e ,pyrite ,fe,s #e4jb #f-f ,pyrolusite ,mn,o #d4ge #a-b ,qu>tz ,si,o #b4fe #g ,s]p5t9e ,mg,si,o7,,oh7 #b4dh #c-d ,silv] ,ag #aj4e #b-c ,sulfur ,s #b4je-b4ji #a-b ,talc ,mg,si,o7,,oh7 #b4g-b4h #a ,topaz ,al,si,o7,f1,,oh7 #c4d-c4f #h ,t\rmal9e ,complex silicate ( #c4j-c4be #g-g boron & alum9um ,uranophane ,ca,o#b,,uo#b,si,o#g;,h,o #c4h-c4i #b-c ,,books ,,ab\t ,,rocks ,,& ,,m9]als ,_m books h be5 writt5 ab\t rocks & m9]als4 ,"s are li/$ bel[1 & x is likely t y\r libr>ian w be able to sugge/ o!rs4 ,nonte*nical ,books = ,beg9n]s ,gett+ ,acqua9t$ ,) ,m9]als1 by ,george ,l4 ,engli% & ,david ,e4 ,j5s54 ,mc,graw-,hill ,book ,company1 ,inc41 ,new ,york1 ,n4 ,y4 7second edition1 #aieh74 ,! ,rock ,book1 by ,c>roll ,l4 ,f5ton & ,mildr$ ,a4 ,f5ton4 ,d\bl$ay ,company1 ,inc41 ,g>d5 ,city1 ,n4 ,y4 7#aidj74 ,m9]al ,collector's ,guide1 by ,david ,e4 ,j5s54 ,w>d's ,natural ,sci5ce ,e/abli%m5t1 ,inc41 ,ro*e/]1 ,n4 ,y4 7#aiec74 ,my ,hobby is ,collect+ ,rocks & ,m9]als1 by ,david ,e4 ,j5s54 ,h>t ,book ,company1 ,new ,york1 ,n4 ,y4 7#aiee74 ,rocks & ,m9]als1 by ,ri*>d ,m4 ,pe>l4 ,b>nes ,noble1 ,new ,york1 ,n4 ,y4 7#aief74 #ajja ,que/ions ,answ]$ ,ab\t ! ,m9]al ,k+dom1 by ,ri*>d ,m4 ,pe>l4 ,dodd1 ,mead ,company1 ,new ,york1 ,n4 ,y4 7#aiei74 ,rocks & ,m9]als1 by ,h]b]t ,s4 ,zim & ,paul ,r4 ,s*aff]4 ,simon & ,s*u/]1 ,inc41 ,new ,york1 ,n4,y4 7#aieg74 ,textbooks & ,o!r ,ref]5ce ,books ,economic ,m9]al ,deposits1 by ,alan ,m4 ,bateman4 ,john ,wiley ,sons1 ,inc41 ,new ,york1 ,n4 ,y4 7second edition1 #aiej74 ,a ,textbook ( ,m9]alogy1 by ,edw>d ,s4 ,dana1 revis$ by ,william ,e4 ,=d4 ,john ,wiley ,sons1 ,inc41 ,new ,york1 ,n4 ,y4 7f\r? edition1 #aicb74 ,indu/rial ,m9]als & ,rocks 7,nonmetallics ,o!r ,?an ,fuels71 ,joseph ,l4 ,gillson1 ,editor-9-,*ief4 ,! ,am]ican ,in/itute ( ,m9+1 ,metallurgical1 & ,petroleum ,eng9e]s1 ,new ,york1 ,n4 ,y4 7?ird edition1 #aifj74 ,dana's ,manual ( ,m9]alogy1 revis$ by ,cornelius ,s4 ,hurlbut1 ,jr4 ,john ,wiley ,sons1 ,inc41 ,new ,york1 ,n4 ,y4 7sev5te5? edition1 #aiei74 ,m9]alogy1 by ,edw>d ,h4 ,kraus1 ,walt] ,f4 ,hunt1 & ,lewis ,s4 ,ramsdell4 ,mc,graw-,hill ,book ,company1 ,inc41 ,new ,york1 ,n4 ,y4 7fif? edition1 #aiei74 ,nonmetallic ,m9]als1 by ,raymond ,b4 ,ladoo & ,w4 ,m4 ,mey]s4 ,mc,graw-,hill ,book ,company1 ,inc41 ,new ,york1 ,n4 ,y4 7second edition1 #aiea74 ,rocks & ,rock ,m9]als1 by ,l\is ,v4 ,pirsson1 revis$ by ,adolph ,knopf4 ,john ,wiley & ,sons1 ,inc41 ,new ,york1 ,n4 ,y4 7?ird edition1 #aidg74 ,a ,field ,guide to ,rocks & ,m9]als1 by ,fr$]ick ,h4 ,p\gh4 ,h\ghton ,miffl9 ,company1 ,bo/on1 ,mass4 7?ird edition1 #aifj74 ,m9]al ,facts & ,problems1 by ! ,/aff ( ! ,bureau ( ,m9es4 ,u4 ,s4 ,bureau ( ,m9es ,bullet9 #ehe4 ,u4 ,s4 ,gov]nm5t ,pr9t+ ,(fice1 ,wa%+ton1 ,d4 ,c4 7#aifj74 ,select$ ,ref]5ces on ,texas ,rocks & ,m9]als ,entries m>k$ ) an a/]isk are publi%$ by ! ,bureau ( ,economic ,geology1 ,! ,univ]sity ( ,texas1 ,au/94 ,^? n out ( pr9t are di/ribut$ at nom9al sale price1 & a li/ ( publications w be s5t on reque/4 ,^! publications c be consult$ at _m public libr>ies & ,*amb] ( ,comm]ce (fices4 99,report on ! ,pavitte ,silv]-,copp] ,prospect 9 ,burnet ,c\nty1 ,texas1 by ,v4 ,e4 ,b>nes4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,m9]al ,res\rce ,survey ,circ4 #e 7#aicf74 99,report on ! ,%]idan ,copp] ,prospect 9 ,burnet ,c\nty1 ,texas1 by ,v4 ,e4 ,b>nes4 ,univ4 ,texas1 ,bur4 ,econ4 ,geol4 ,m9]al ,res\rce ,survey ,circ4 #i 7#aicf74 99,build+ ,/ones ( ,c5tral ,texas1 by ,v4 ,e4 ,b>nes1 ,r4 ,f4 ,dawson1 & ,g4 ,a4 ,p>k9son4 ,univ4 ,texas ,pub4 #dbdf 7#aidg74 99,iron ,ore 9 ! ,llano ,region1 ,c5tral ,texas1 by ,v4 ,e4 ,b>nes4 ,univ4 ,texas1 ,bur4 ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #e 7#aidi74 99,utilization ( ,texas ,s]p5t9e1 by ,v4 ,e4 ,b>nes1 ,d4 ,a4 ,%ock1 & ,w4 ,a4 ,cunn+ham4 ,univ4 ,texas ,pub4 #ejbj 7#aiej74 99,lead ,deposits 9 ! ,upp] ,cambrian ( ,c5tral ,texas1 by ,v4 ,e4 ,b>nes4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #bf 7#aief74 99,m9]al ,res\rces ( ! ,colorado ,riv] ,indu/rial ,developm5t ,association ,area1 by ,j4 ,w4 ,dietri* & ,j4 ,t4 ,lonsdale4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #cg 7#aieh74 99,"s ,uranium ,occurr5ces 9 ,we/ ,texas1 by ,d4 ,h4 ,e>gle4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #bg 7#aief74 99,a ,prelim9>y ,report on ! ,/ratigraphy ( ! ,uranium-,be>+ ,rocks ( ! ,k>nes ,c\nty ,area1 ,s\?-,c5tral ,texas1 by ,d4 ,h4 ,e>gle & ,j4 ,l4 ,snid]4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #cj 7#aieg74 ,! ,br[n ,iron ,ores ( ,ea/]n ,texas1 by ,e4 ,b4 ,eckel4 ,u4 ,s4 ,geol4 ,survey ,bull4 #ijb 7#aich74 99,! ,ru/l] ,spr+s ,sulphur ,deposits z a ,s\rce ( ,f]tiliz]1 by ,g4 ,l4 ,evans4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #a 7#aidf74 ,orig9 ( ! ,gulf ,coa/ ,salt-,dome ,sulphur ,deposits1 by ,h]b]t ,w4 ,feely & ,j4 ,lawr5ce ,kulp4 ,bull4 ,am]4 ,assoc4 ,petrol4 ,geol41 vol4 #da1 pp4 #ahjb-ahec 7#aieg74 99,pegmatites ( ! ,van ,horn ,m\nta9s1 ,texas1 by ,p4 ,t4 ,flawn4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #i 7#aiea74 99,! ,hazel ,copp]-,silv] ,m9e1 ,culb]son ,c\nty1 ,texas1 by ,p4 ,t4 ,flawn4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #af 7#aieb74 99,basem5t ,rocks ( ,texas & ,s\!a/ ,new ,mexico1 by ,p4 ,t4 ,flawn4 ,univ4 ,texas ,pub4 #efje 7#aief74 99,texas ,m9]s ,boo/ ,talc ,output1 by ,p4 ,t4 ,flawn4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #ce 7#aieh74 99,geology & ,m9]al ,deposits ( ,pre-,cambrian ,rocks ( ! ,van ,horn ,area1 ,texas1 by ,p4 ,b4 ,k+ & ,p4 ,t4 ,flawn4 ,univ4 ,texas ,pub4 #ecja 7#aiec74 99,igne\s ,rocks ( ! ,balcones ,fault ,region ( ,texas1 by ,j4 ,t4 ,lonsdale4 ,univ4 ,texas ,bull4 #bgdd 7#aibg74 ,m9]al ,res\rces ( ! ,llano-,burnet ,region1 ,texas1 ) an ,acc\nt ( ! ,pre-,cambrian ,geology1 by ,sidney ,paige4 ,u4 ,s4 ,geol4 ,survey ,bull4 #dej 7#aiaa74 99,m9]al ,res\rces ( ! ,texas ,coa/al ,pla9 7,prelim9>y ,report71 by ,j4 ,m4 ,p]k9s & ,j4 ,t4 ,lonsdale4 ,univ4 ,texas1 ,bureau ,econ4 ,geol4 ,m9]al ,res\rce ,circ4 #ch 7#aiee74 ,geology & ,ore ,deposits ( ! ,%aft] ,m9+ ,di/rict1 ,presidio ,c\nty1 ,texas1 by ,c4 ,p4 ,ross4 ,u4 ,s4 ,geol4 ,survey ,bull4 #ibh-;,b 7#aidc74 99,! ,geology ( ,texas1 ,vol4 ,,ii1 ,/ructural & ,economic ,geology1 by ,e4 ,h4 ,sell>ds1 ,c4 ,l4 ,bak]1 & o!rs4 ,univ4 ,texas ,bull4 #cdja 7#aice74 99,texas ,m9]al ,res\rces1 by ,e4 ,h4 ,sell>ds & o!rs4 ,univ4 ,texas ,pub4 #dcja 7#aidf74 99,geological ,res\rces ( ! ,tr9ity ,riv] ,tribut>y ,area 9 ,texas & ,oklahoma1 by ,h4 ,b4 ,/5zel1 ,a4 ,e4 ,weiss5born1 & o!rs4 ,univ4 ,texas ,pub4 #dhbd 7#aidh74 ,uranium at ,palangana ,salt ,dome1 ,duval ,c\nty1 ,texas1 by ,a4 ,d4 ,weeks & ,d4 ,h4 ,e>gle4 ,9 ,u4 ,s4 ,geol4 ,survey ,pr(4 ,pap] #djj-;,b 7#aifj74 ,geology ( ! ,quicksilv] ,deposits ( ! ,t]l+ua ,di/rict1 ,texas1 by ,r4 ,g4 ,yates & ,g4 ,a4 ,?ompson4 ,u4 ,s4 ,geol4 ,survey ,pr(4 ,pap] #cab 7#aiei74 ,,gloss>y ,amorph\s--)\t cry/all9e /ructure & !re=e )\t regul> =m4 ,balcones fault zone--a sy/em ( faults ext5d+ f nor? ( ,waco 9 ,mc,lennan ,c\nty1 ?r\gh ,travis & ,bex> c\nties1 to ne> ,del ,rio 9 ,val ,v]de ,c\nty 7see p4 #db74 ,b\ld]--a l>ge rock or m9]al fragm5t t has a diamet] great] ?an #bef millimet]s 7ab\t #aj in*es74 ,breccia--a rock made up ( %>p-corn]$1 cem5t$ fragm5ts ) diamet]s great] ?an #b millimet]s 7ab\t _/ ( an in*74 ,cambrian--! e>lie/ p]iod ( ! ,paleozoic ,era 7see p4 #c74 ,c5ozoic--! pres5t era1 "o ( ! great divisions ( geologic "t 7see p4 #c74 ,?is era began ab\t #fc million ye>s ago4 ,cla/ic--made up ( brok5 fragm5ts ( rocks or m9]als4 ,cleavage--occurs :5 m9]als split along smoo? flat surfaces t are p>allel to possible cry/al faces4 ,^! planes z well z cry/al faces are controll$ by ! cry/al lattice or atomic /ructures ( ! m9]als4 ,cleavage fragm5t--a m9]al specim5 t has be5 brok5 along its planes ( cleavage4 ,cobble--a rock or m9]al fragm5t t has a diamet] betwe5 #fd & #bef millimet]s 7ab\t #b & #aj in*es74 ,con*oidal--a curv$ fracture surface %ap$ l ! inside ( a %ell or spoon4 ,conglom]ate--a rock compos$ ( cem5t$1 r\nd$ rock or m9]al fragm5ts1 mo/ ( :i* are ( gravel size4 ,cretace\s--! ?ird & late/ p]iod ( ! ,mesozoic ,era 7see p4 #c74 ,cryptocry/all9e--made up ( t9y cry/all9e p>ticles t are too small to be di/+ui%$ ev5 "u high magnification4 ,cry/all9e--hav+ a def9ite1 ord]ly int]nal /ructure4 ,cube--a solid t has six equal1 squ>e sides4 ,dodecah$ron--a solid t has twelve plane1 f\r-sid$ faces4 ,elem5t--a basic build+ block ( all matt]1 :i* _c be sep>at$ into diff]5t sub/ances by ord9>y *emical means4 ,eoc5e--! second epo* ( ! ,t]ti>y ,p]iod 7see p4 #c74 ,epo*--a unit ( geologic "t t is a subdivision ( a p]iod4 ,era--a major division ( geologic "t1 :i* consi/s ( sev]al p]iods4 ,extrusive rocks--igne\s rocks =m$ f magma t 0 extrud$ on ! e>?'s surface4 ,fault--a break 9 ! rocks or /rata ( ! e>?'s cru/ along :i* movem5t or slippage has tak5 place4 ,fluid--a sub/ance made up ( p>ticles t c move freely ab\t2 x c be a liquid or a gas4 ,=mation--rocks or /rata t are recogniz$ & mapp$ z a unit4 ,fracture--! k9d ( surface obta9$ if a m9]al is brok5 9 a diff]5t direction f t ( ! cleavage or p>t+4 ,commonly1 fracture surfaces are r\gh1 unev51 or curv$1 :]eas cleavage surfaces are smoo?4 ,geologic map 7areal7--%[s ! ext5t & di/ribution ( =mations expos$ at ! e>?'s surface4 ,granul>--! texture ( a rock or m9]al t is made up ( visible gra9s4 ,if all ! gra9s are ab\t ! same size1 ! t]m equigranul> is us$4 ,granule--a rock or m9]al fragm5t t has a diamet] ( f #b to #d millimet]s 7ab\t _/ to _/ ( an in*74 ,gravel--uncem5t$ rock or m9]al fragm5ts t h diamet]s great] ?an #b millimet]s 7ab\t _/ ( an in*74 ,gulf ,coa/al ,pla9--an area t ext5ds1 9 ,texas1 f ! ,gulf ( ,mexico to ! ,balcones fault zone & 9 :i* ,quat]n>y1 ,t]ti>y1 & ,upp] ,cretace\s /rata crop out at ! surface 7see p4 #db74 ,high ,pla9s--an area 9 nor?we/ ,texas ext5d+ f ! ,pecos ,riv] valley nor? to ! ,oklahoma-,texas b\nd>y 7see p4 #db74 ,igne\s rocks--rocks =m$ by ! cool+ & h>d5+ ( hot1 molt5 rock mat]ial4 ,intrusive rocks--igne\s rocks t h =m$ bel[ ! surface ( ! e>?4 ,lava--molt5 rock mat]ial t has p\r$ out onto ! e>?'s surface f volcanoes2 also ! rock t is =m$ aft] ! molt5 mat]ial has cool$ & h>d5$4 ,llano uplift--an area 9 c5tral ,texas :]e ,precambrian & e>ly ,paleozoic rocks occur at ! e>?'s surface 7see p4 #db74 ,magma--hot1 molt5 rock mat]ial f :i* igne\s rocks =m4 ,massive--9 a mass1 )\t a regul> or complete =m4 ,mesozoic--an era1 "o ( ! great divisions ( geologic "t 7see p4 #c74 ,?is era began ab\t #bcj million ye>s ago & la/$ until ab\t #fc million ye>s ago4 ,metamorphic rock--rock =m$ f igne\s or s$im5t>y rocks t are alt]$ by heat1 pressure1 & fluids bel[ ! e>?'s surface4 ,mioc5e--! f\r? epo* ( ! ,t]ti>y ,p]iod 7see p4 #c74 ,mississippian--! fif? p]iod ( ! ,paleozoic ,era 7see p4 #c74 ,nodule--a small1 r\nd$ mass or lump4 ,octah$ron--a solid t has eight triangul> faces4 ,opaque--no light c pass ?r\gh4 ,ordovician--! second p]iod ( ! ,paleozoic ,era 7see p4 #c74 ,paleozoic--an era1 "o ( ! great divisions ( geologic "t 7see p4 #c74 ,?is era began at ! end ( ,precambrian "t & la/$ until ab\t #bcj million ye>s ago4 ,p>t+--occurs :5 a m9]al breaks along a flat surface t is n a true cleavage plane4 ,pebble--a rock or m9]al fragm5t t has a diamet] betwe5 #d & #fd millimet]s 7ab\t _/ & #b in*es74 ,p5nsylvanian--! six? p]iod ( ! ,paleozoic ,era 7see p4 #c74 ,p]iod--a unit ( geologic "t1 a subdivision ( an era4 ,p]mian--! la/ p]iod ( ! ,paleozoic ,era 7see p4 #c74 ,physiographic outl9e map--%[s location ( natural regions 7p4 #db74 ,playa lake--a tempor>y %all[ lake 9 a ne>ly level1 clos$ bas91 :i* has no dra9age outlet4 ,plei/oc5e--! fir/ epo* ( ! ,quat]n>y ,p]iod 7see p4 #c74 ,plioc5e--! la/ epo* ( ! ,t]ti>y ,p]iod 7see p4 #c74 ,precambrian--comprises ! ,e>ly & ! ,late ,precambrian ,eras1 ! e>lie/ great divisions ( geologic "t4 ,rocks t =m$ m ?an #fjj million ye>s ago are kn[n z ,precambrian rocks4 ,pyritoh$ron--a solid t has twelve #e-sid$ faces4 ,quat]n>y--! pres5t p]iod ( geologic "t2 ! second p]iod ( ! ,c5ozoic ,era 7see p4 #c74 ,rec5t--! pres5t epo* ( geologic "t2 ! second epo* ( ! ,quat]n>y ,p]iod 7see p4 #c74 ,sectile--describes mat]ial1 su* z soap1 t c be cut smoo?ly ) a knife4 ,s$im5ts--mat]ial deposit$ by wat]1 w9d1 or ice on ! e>?'s surface4 ,s$im5t>y rocks--rocks made up ( s$im5ts4 ,s]ies--a subdivision ( a sy/em t includes all rocks =m$ dur+ an epo*4 ,specific gravity--! ratio ( ! weight ( a sub/ance to ! weight ( an equal volume ( wat]4 ,/reak--! color ( ! p[d] ( a m9]al4 ,sy/em--all rocks =m$ dur+ a p]iod4 ,t]ti>y--! fir/ p]iod ( ! ,c5ozoic ,era 7see p4 #c74 ,transluc5t--light w pass ?r\gh1 b objects _c be se54 ,transp>5t--light w pass ?r\gh1 & objects c be se54 ,trans-,pecos--area ( ,texas locat$ we/ ( ! ,pecos ,riv] 7see p4 #db74 ,volcanic rocks--igne\s rocks t h =m$ on ! e>?'s surface2 extrusive rocks4 ,index ,a acid3 #ah1 #bb acid te/s 7see also *emical te/s73 #ah act9olite3 #hb s*i/3 #hg agate3 #ba1 #hc agatiz$ wood3 #bj1 #hd age1 e>?'s cru/3 #b alaba/]3 #fe albite3 #ee alkali lakes3 #ff1 #hc ,allamoore3 #hg1 #ic alloys3 #eb alm&ite3 #eh ,alp9e3 #eg1 #gh1 #hb1 #ij ,altuda ,m\nta93 #eg1 #ij amalgam3 #ea amazon/one3 #ef ame?y/3 #cg1 #hb ,ame?y/ ,hill3 #hb amorph\s m9]als1 def9ition (3 #ae amphibole asbe/os3 #bi1 #cc1 #cd1 #dd ,&]son ,c\nty3 #gj ,&rews ,c\nty3 #hc ,angel9a ,c\nty3 #eb anhydrite3 #bh1 #bi1 #cj1 #ce1 #cf1 #dc1 #fe1 #ff1 #ia an?ophyllite3 #ic antigorite3 #hg ,apa*e ,m\nta9s3 #fe apatite3 #gb ,ar*] ,c\nty3 #eb arg5tite3 #bf1 #bg1 #hi1 #ij arg5tif]\s gal5a3 #eg1 #ij ,arm/rong ,c\nty3 #gi asbe/os3 #dc amphibole3 #bi1 #cc1 #cd1 #dd *rysotile3 #dd1 #hg a%1 volcanic3 #da1 #ig augite3 #de ,au/93 #df1 #fb autunite3 #ig azurite3 #ce1 #eb1 #ec1 #ed ,b ,babyhead3 #gb ,balcones fault zone3 #aj1 #db1 #de1 #hh ,b&]a ,c\nty3 #de ,b>+] ,hill pegmatite3 #hj b>ite3 #ae1 #bh1 #ca1 #cb1 #ce1 #cf1 #ch1 #dd1 #dh b>ium3 #de ,b>rilla ,m\nta9s3 #he ,baylor ,c\nty3 #de1 #eb1 #ih basal cleavage3 #gf1 #ic1 #id basalt3 #dj1 #da1 #de basem5t3 #b1 #i ,ba/rop ,c\nty3 #fd ,bell ,c\nty3 #fi b5tonite3 #ea1 #eb b]yllium3 #hj ,big ,b5d area3 #i1 #db1 #ea1 #ge1 #gg ,big ,bran* ,gneiss3 #ei biotite3 #cb1 #cc1 #cd1 #gf ,bird m9e3 #ij ,blanco ,c\nty3 #dd1 #eh1 #ei1 #fa1 #gj1 #hc1 #hg1 #id black mica 7see biotite7 bla/ furnace3 #gj1 #ga bla/ s&3 #hf blea*+ clay3 #ea blue copp]3 #ec ,bo]ne3 #ah ,bol+ salt dome3 #ia books ab\t rocks & m9]als3 #bd1 #ci1 #ajj brass3 #eb braunite3 #bf1 #bg1 #gc ,brazoria ,c\nty3 #ia ,brazos ,c\nty3 #ih ,brazos ,riv]1 ,d\ble ,m\nta9 ,=k & ,salt ,=k (3 #dc breccia3 #ab1 #da1 #ha ,brew/] ,c\nty3 #de1 #df1 #dg1 #di1 #ej1 #eg1 #fe1 #gj1 #gf1 #gg1 #gh1 #hb1 #hd1 #he1 #ij brim/one3 #ij bronze3 #eb ,brooks ,c\nty3 #fd ,br[n1 ,?omas ,e43 vii ,br[n ,c\nty3 #de1 #di br[n iron ore 7see also limonite73 #gj ,bryan ,m\nd salt dome3 #ia build+ s&3 #he ,burnet3 #ef1 #hj1 #ig ,burnet ,c\nty3 #ah1 #ec1 #ed1 #ee1 #ef1 #eh1 #ei1 #fj1 #fa1 #fb1 #fc1 #gj1 #gf1 #gi1 #hj1 #ha1 #hb1 #hc1 #ig ,c calc>e\s s9t] & tufa3 #df calcite3 #g1 #ad1 #ah1 #ai1 #bj1 #ba1 #bh1 #cj1 #ca1 #cb1 #cd1 #ce1 #cf1 #ch1 #de1 #df1 #di1 #ej1 #ea1 #ed1 #ef1 #fd1 #fh1 #ge1 #hf1 #hg1 #hh1 #ia dog-too? sp>3 #df1 #dg ,caldwell ,c\nty3 #hh cali*e3 #df1 #dg ,cambrian3 #b1 #c1 #ee1 #eh1 #fi1 #hf ,cam]on ,c\nty3 #ff ,capitan reef lime/one3 #a ,capitol build+1 ,texas ,/ate3 #fb cap-rock3 #ia1 #ib c>ats3 #fj c>bon3 #fb1 #fc c>boniz$ wood3 #bj c>notite3 #cj1 #ie1 #ig ,c>rizo ,m\nta9s3 #fg1 #hc1 #ie ,casey1 ,miss ,joseph9e3 vii ,cass ,c\nty3 #gj cassit]ite3 #bg1 #cb1 #dg ,ca/ile ,gypsum3 #ia ,catah\la /rata3 #gh1 #hf1 #ig cave deposits3 #ah caves3 #ah1 #ai1 #di ,cav]ns ( ,sonora3 #ai ,c$> ,lake3 #hc ,c$> ,p>k3 #gj cele/ite3 #bj1 #bh1 #cj1 #ce1 #ch1 #dh cem5t+ mat]ials3 #ab1 #df1 #fg1 #gj1 #hf c]>gyrite3 #bh1 #bi1 #cd1 #cg1 #hi1 #ij c]ium3 #hj *alc$ony 7see also agate73 #af1 #ba1 #de1 #gh1 #ha1 #hc1 #hf *alcocite3 #ba1 #bf1 #bg1 #eb1 #ed1 #gc1 #hi *alcopyrite3 #bf1 #eb1 #ec1 #ed1 #fj *alk3 #dj1 #fi *emical elem5ts3 #g *emical s$im5ts3 #ab *emical te/s3 #ah1 #dc1 #df1 #dg1 #di1 #eb1 #ec1 #ed1 #fd1 #fh1 #ge ,*]okee ,c\nty3 #gj *]t3 #ai1 #dj1 #ha1 #hd *essylite3 #ec *9a clay3 #ea ,*9ati ,m\nta9s3 #de1 #eg1 #fb1 #he ,*isos ,m\nta9s3 #de1 #fb1 #he *lorite3 #ic s*i/3 #hg *rysotile3 #dd1 #hg1 #hh asbe/os3 #dd1 #hg c9nab>3 #cf1 #di cla/ic rocks3 #ab clay3 #dj1 #de1 #di1 #ea1 #gj1 #hf1 #hh1 #ia b5tonite3 #de1 #ea1 #eb blea*+ clay3 #ea *9a clay3 #ea kaol93 #ea clay m9]als3 #ea ,clay ,c\nty3 #eb ,cle> ,creek area3 #fc cleavage3 #ag basal3 #gf1 #ic1 #id cubic3 #ag1 #eg1 #fe octah$ral3 #ef1 #eg pyramidal3 #gd rhomboh$ral3 #df1 #ed ,clem5s salt dome3 #ia ,coal ,creek s]p5t9e3 #hg1 #hh ,coke ,c\nty3 #bj1 #di ,coleman ,c\nty3 #hf color ( m9]als3 #af columns3 #ah ,comal ,c\nty2 #de1 #fi ,coman*e ,c\nty3 #di common opal3 #gh composition ( m9]als3 #ii concretions3 #ai conglom]ate3 #aa1 #ab1 #da1 #ee1 #ha gneiss3 #ei contact metamorphism3 #ac copp]3 #eb1 #ei1 #ij blue copp]3 #ec glance3 #eb gre5 copp] c>bonate3 #ec m9]als3 #eb pyrites3 #ec yell[ copp] ore3 #ec coqu9a3 #da1 #fi ,crane ,c\nty3 #ff ,cretace\s3 #b1 #c1 #bj1 #ba1 #de1 #df1 #di1 #ea1 #ee1 #eg1 #fj1 #fe1 #fh1 #fi1 #gj1 #gd1 #ge1 #hd1 #hf1 #hh cryptocry/all9e qu>tz3 #ha1 #hd cry/al1 def9ition (3 #ad cry/als1 tw9n$3 #df1 #fc cry/all9e m9]als1 def9ition (3 #ad ,crosby ,c\nty3 #gi cru/1 e>?'s3 #b cubic cleavage3 #ag1 #eg1 #fe ,culb]son ,c\nty3 #a1 #de1 #eb1 #ec1 #eh1 #ei1 #fj1 #fe1 #ge1 #gi1 #hc1 #ij1 #ia1 #ie ,d ,da+]field3 #gj ,dallas3 #hh ,damon ,m\nd salt dome3 #ia daught] elem5ts3 #ie1 #if ,davis ,m\nta9s3 #de1 #he1 #ih ,delaw>e ,m\nta9s3 #fe diamond3 #fb diatomace\s e>?3 #gh diatomite3 #dj1 #gh ,dick5s ,c\nty3 #gi1 #ih ,dietri*1 ,john ,w43 vii dikes3 #gb1 #gi dog-too? sp>3 #df1 #dg dolomite3 #bi1 #cj1 #cb1 #cf1 #ch1 #dj1 #dc1 #ed1 #fh1 #ge1 #hg1 #hh dolomitic lime/one3 #fh ,d\ble ,m\nta9 ,=k ( ! ,brazos ,riv]3 #dc d\ble refraction3 #df dravite3 #ie ,duval ,c\nty3 #gh1 #hc1 #ia1 #ig dynamic metamorphism3 #ad ,e ,eagle ,flat3 #ic ,eagle ,m\nta9s3 #ef1 #eg1 #ij1 #ie e>?'s cru/3 #b ea/ ,texas3 #gj ,ector ,c\nty3 #gi ,edw>ds ,lime/one3 #fh1 #fi1 #hd eff]vesc5ce 9 acid3 #ah ,el ,capitan ,peak3 #a elem5ts3 #g1 #h1 #ie1 #if ,ell5burg] /rata3 #ee1 #hd ,el ,paso3 #dh1 #eh1 #he1 #hh ,el ,paso ,c\nty3 #dh1 #eh1 #fb epo*3 #b era3 #b erosion3 #aa extrusive igne\s rocks1 def9ition (3 #i ,f ,fairl&3 #ed ,falfurrias3 #fd ,fannett salt dome3 #ia ,fayette ,c\nty3 #eb1 #fd1 #hd1 #ih feldsp>3 #h1 #bi1 #cj1 #ca1 #cc1 #cd1 #ce1 #cg1 #de1 #ea1 #ee1 #ei1 #fa1 #gb1 #gi1 #hj1 #he1 #hf albite3 #ee amazon/one3 #ef microl9e3 #ee1 #ef1 #fa or?oclase3 #ee1 #fa fibr\s gypsum3 #fd1 #fe filt]+ s&3 #hf ,fi%] ,c\nty3 #bj1 #di1 #eh1 #fe ,flawn1 ,pet] ,t43 vii fl9t3 #hd fl[/one3 #ah fl[ /ructure3 #he fluorite3 #bi1 #cb1 #cd1 #ce1 #cg1 #ch1 #ef1 #gb ,fo>d ,c\nty3 #eb1 #eh foliation3 #hg fool's gold3 #ec1 #hj =mation3 #f ,=t ,b5d ,c\nty3 #ia ,=t ,wor?3 #hh fracture ( m9]als3 #ag fragm5tal rocks3 #ab ,frankl9 ,m\nta9s3 #dh1 #eh1 #fb1 #he ,fras* me?od ( sulfur m9+3 #ia1 #ib ,fr$onia3 #fg ,fre]3 #gh1 #hc furnace 7see bla/ furnace2 op5-he>? furnace7 ,g gabbro3 #hg gneiss3 #ei ,ga9es ,c\nty3 #hc gal5a3 #ag1 #bf1 #eg1 #hi1 #ij arg5tif]\s3 #eg1 #ij ,galve/on ,c\nty3 #ia ,gamble prospect3 #fg gamma rays3 #if g>net3 #ca1 #cc1 #cd1 #cg1 #eh1 #he1 #hg ,g>za ,c\nty3 #ig ,geig] c\nt]3 #if gem/ones3 #ef1 #eh1 #gg1 #hb1 #id1 #ie geode3 #ai1 #df1 #di1 #hb geologic map3 #d1 #e geologic "t scale3 #b1 #c geologi/s3 #b geology3 #b ,gillespie ,c\nty3 #dd1 #de1 #ee1 #eh1 #ei1 #fj1 #fa1 #fe1 #gf1 #hj1 #hb1 #hc1 #hg1 #hh1 #id glass1 natural3 #i1 #gg1 #he1 #ig glass s&3 #he-hf glauconite3 #gj1 #gc gloss>y3 #ajb-ajc gneiss3 #ac1 #da1 #ee1 #ef1 #ei1 #fg1 #gb1 #gc1 #gd1 #gf1 #ha1 #hg1 #ic1 #ig conglom]ate3 #ei gabbro3 #ei granite3 #ei hornbl5de3 #ei mica3 #ei goe?ite3 #gj gold3 #bf1 #ea1 #ei1 #hj1 #ij fool's3 #ec1 #hj ,gonzales ,c\nty3 #eb1 #hd1 #ig ,gr& ,sal9e salt dome3 #ff granite3 #b1 #h1 #i1 #ac1 #da1 #dh1 #ee1 #ef1 #ei1 #fa1 #gb1 #gf1 #gi1 #ha1 #he1 #hg1 #id1 #ie gneiss3 #ei opal9e3 #gb ,granite ,m\nta93 #fb ,granite ,%oals ,lake3 #ef granules3 #he graphite3 #bf1 #bg1 #fb1 #ge s*i/3 #fc1 #hg gravel3 #ab1 #da1 #ia gre5 copp] c>bonate3 #ec gre5s&s3 #gj ,grit3 #id grossul>ite3 #eh gr\p3 #f ,guadalupe ,m\nta9s1 ,peak3 #a ,gulf ,coa/3 #ia ,gulf ,coa/al ,pla93 #bj1 #db1 #dc1 #df1 #ea1 #eb1 #eh1 #fj1 #fe1 #ff1 #gh1 #hc1 #hd1 #hf1 #hg1 #ib1 #ig1 #ih ,gulf salt dome3 #ia ,gyp ,hill salt dome3 #fd gypsite3 #fe gypsum3 #bh1 #bi1 #cj1 #cb1 #cf1 #cg1 #dc1 #fc1 #gj1 #he1 #ia alaba/]3 #fe fibr\s gypsum3 #fd1 #fe rock gypsum3 #dj1 #fe rosettes3 #fc1 #fd sat9 sp>3 #fd sel5ite3 #fc1 #fd1 #gf ,h halite3 #bh1 #cb1 #cd1 #ce1 #cf1 #ch1 #dj1 #dc1 #fe1 #ia h& l5s3 #bb ,h>deman ,c\nty3 #eb1 #eh1 #fd1 #fe h>dness ( m9]als3 #af1 #ii ,h>ris1 ,bill ,m43 vii ,h>ris1 ,john ,s43 vii ,h>ris ,c\nty3 #fe1 #ff ,h>tley ,c\nty3 #gi ,hays ,c\nty3 #de ,hazel ,=mation3 #eb ,hazel m9e3 #eb1 #ec1 #ij ,hea? m9e3 #fj hematite3 #bf1 #bg1 #cf1 #ff1 #ge1 #hd1 #hf specul>3 #fg ,h5d]son ,c\nty3 #gj ,high ,isl& salt dome3 #ia ,high ,pla9s3 #db1 #df1 #ea1 #fe1 #ff1 #gh1 #gi1 #hc1 #hg1 #ig1 #ih ,hockley salt dome3 #fe1 #ff holl&ite3 #bf1 #bg1 #bh1 #gc1 #gd ,honey ,creek area3 #hg hornbl5de3 #h1 #ei1 #fa gneiss3 #ei s*i/3 #hg horn silv]3 #ij ,hosk9s ,m\nd salt dome3 #ia ,h\/on3 #gj ,h[>d ,c\nty3 #de1 #fj ,hudspe? ,c\nty3 #de1 #eb1 #ec1 #ee1 #ef1 #eg1 #eh1 #ei1 #fj1 #fb1 #fe1 #ff1 #fg1 #ge1 #gi1 #hb1 #hc1 #ij1 #ic1 #ie ,humphreys1 ,alan3 vii ,hut*9son ,c\nty3 #ff hyalite3 #gh hydro*loric acid 7see also *emical te/s73 #ah1 #bb ,i id5tification *>ts3 #bd igne\s rocks1 def9ition (3 #i intrusive igne\s rocks1 def9ition (3 #i ,irion ,c\nty3 #fj iron3 #ei1 #ff1 #fg1 #fi1 #gj1 #gb1 #gc ,iron ,m\nta93 #gc ,j ,jackson /rata3 #ig jasp]3 #ha1 #hd ,jasp] ,c\nty3 #eb ,jeff ,davis ,c\nty3 #de1 #ea1 #gd1 #gh1 #he ,jeff]son ,c\nty3 #ia ,johnson ,c\nty3 #fi ,k kaol93 #ea kaol9ite3 #ea k>ats3 #fj ,k>nes ,c\nty3 #ig1 #ih ,katemcy3 #id ,k5dall ,c\nty3 #ah ,k5$y ,c\nty3 #ff ,k5t ,c\nty3 #ih kidney ore3 #fg ,k+1 ,elb]t ,a41 ,jr43 vii ,k+ ,c\nty3 #eb ,k9ney ,c\nty3 #de ,kleb]g ,c\nty3 #ff ,knox ,c\nty3 #eb ,l label+ rock & m9]al specim5s3 #bc labradorite3 #de ,lake ,bu*anan3 #hj1 #hc ,lamb ,c\nty3 #gi ,lampasas ,c\nty3 #bj1 #dh1 #di1 #hh lava3 #i lead3 #eg1 #ij ,leakey3 #ea ,lee ,c\nty3 #fd1 #hd l5s3 #bb ,lib]ty ,c\nty3 #ia lime3 #fi lime/one3 #ab1 #ac1 #ah1 #ai1 #dj1 #dc1 #de1 #df1 #di1 #ed1 #ee1 #ef1 #eg1 #eh1 #fj1fh1 #gd1 #ge1 #gf1 #hd1 #hh1 #ij1 #ia *alk3 #fi dolomitic3 #fh li?ographic3 #fi olitic3 #fi pulv]ul5t3 #da1 #fi limonite3 #ai1 #bg1 #bh1 #cj1 #cb1 #gj1 #ge1 #ha1 #hf li?ographic lime/one3 #fi ,live ,oak ,c\nty3 #de1 #ig llanite3 #da1 #ga1 #ha ,llano3 #fj1 #fc1 #gb1 #gc1 #ie ,llano ,c\nty3 #dd1 #de1 #ee1 #ef1 #eh1 #ei1 #fj1 #fa1 #fc1 #gj1 #ga1 #gb1 #gc1 #gf1 #gh1 #hj1 #hc1 #hg1 #hh1 #id1 #ie ,llano uplift3 #aj1 #ah1 #db1 #dd1 #eb1 #ee1 #ef1 #eh1 #ei1 #fj1 #fa1 #fb1 #fc1 #fg1 #gj1 #gb1 #gf1 #gg1 #gi1 #hj1 #hb1 #hc1 #hd1 #he1 #hf1 #hg1 #hh1 #ic1 #id1 #ie ,lone ,grove3 #fc ,lone ,/>3 #gj ,longhorn ,cav]n3 #ah ,long ,po9t salt dome3 #ia ,lonsdale1 ,john ,t43 vii lu/] ( m9]als3 #af ,lytton ,spr+s oil field3 #hh ,m ,macon1 ,james ,w43 vii magma3 #i magnesium1 s\rce (3 #ee magnetite3 #bh1 #fg1 #gj1 #gb1 #he1 #hg1 #ic mala*ite3 #cd1 #eb1 #ec1 #ed ,malone ,m\nta9s3 #fe manganese3 #gc1 #ge map-- geologic3 #d-e physiographic outl9e3 #db ,m>a?on area3 #db1 #hd1 #hh m>ble3 #ac1 #ad1 #dj1 #df1 #ed1 #ge ,m>ble ,falls3 #fb ,m>ion ,c\nty3 #gj m>tite3 #fg ,mason3 #gd ,mason ,c\nty3 #dh1 #ee1 #eh1 #ei1 #fj1 #fa1 #fg1 #gb1 #gc1 #gd1 #gf1 #hj1 #hc1 #id masses1 cry/all9e1 def9ition (3 #ad ,matagorda ,c\nty3 #ia ,mayfield prospect3 #gd ,mc,culloch ,c\nty3 #hh ,m$9a ,c\nty3 #de ,m5>d ,c\nty3 #fe m]cury3 #h1 #di1 #ej1 #ea metamorphic rocks1 def9ition (3 #ab metamorphism1 def9ition (3 #ac1 #ad mica 7see also biotite2 muscovite73 #h1 #fj1 #fa1 #fc1 #fd1 #gb1 #gf1 #gi1 #hj1 #he1 #hg mica gneiss &_/or s*i/3 #ei1 #gf1 #hg ,mica ,m9e area3 #eh1 #gf1 #gg1 #gi microcl9e3 #ee1 #ef1 #fa milky qu>tz3 #hb ,mills ,c\nty3 #di m9]al id5tification *>ts3 #bd m9]alogi/s3 #b m9]als1 def9ition (3 #g1 #ad1 #ae ,mississippian3 #c1 #ee1 #fi1 #hh ,mit*ell ,c\nty3 #ff ,mohs scale ( h>dness3 #af1 #ag molybd5ite3 #fc montmorillonite3 #ea ,morris ,c\nty3 #gj moss agate3 #hd ,moss ,bluff salt dome3 #ia muriatic acid3 #bb muscovite3 #ca1 #cb1 #cd1 #cg1 #ch1 #gf ,n ,nacogdo*es ,c\nty3 #gj ,na% salt dome3 #ia native elem5ts3 #h native m]cury3 #h native silv]3 #bf1 #hi nodule3 #ai1 #dd1 #di ,nolan ,c\nty3 #bj1 #di1 #fc1 #fd1 #fe nor?-c5tral ,texas3 #dc1 #ea1 #eb1 #fi1 #gj1 #hf1 #hh ,o ,oakville /rata3 #ig obsidian3 #dj1 #gg occurr5ce ( m9]als3 #ad o*]1 r$3 #fg octah$ral cleavage3 #ef1 #eg oil %ale3 #hh oliv9e3 #hh onyx3 #hd olitic lime/one3 #fi opal3 #ba1 #bi1 #cj1 #ca1 #ce1 #cg1 #ch1 #gh1 #hf opal9e granite3 #gb opaliz$ wood3 #bj1 #gh1 #hd op5-he>? furnace3 #gj1 #gb ,or*>d salt dome3 #ia ,ordovician3 #c1 #ee1 #fi1 #hd or?oclase3 #ee1 #fa ,p ,packsaddle ,m\nta93 #hg ,packsaddle ,s*i/3 #hg ,palangana salt dome3 #ia1 #ig paleontologi/s3 #b p>t+ ( m9]als3 #ag ,pavitte prospect3 #ec ,pecos ,c\nty3 #i ,pecos ,riv]3 #fe1 #gd1 #ge pegmatite3 #da1 #ee1 #ef1 #eh1 #gf1 #gg1 #gi1 #ha1 #id1 #ie ,b>+] ,hill3 #hj ,p5nsylvanian3 #c1 #de1 #ea1 #ee1 #fi1 #gj1 #hf1 #hh p]idotite3 #hh p]iod3 #b ,p]mian3 #a1 #c1 #bj1 #ba1 #dc1 #de1 #di1 #eb1 #ee1 #fd1 #fe1 #fi1 #hf1 #ij ,p]mian bas93 #db1 #dc1 #fe1 #ff petrifi$ wood3 #bj1 #eb1 #gh1 #hd petrologi/s3 #b ph5ocry/s3 #he physiographic outl9e map3 #db pit*bl5de3 #bh1 #ie1 #ig plac] deposits3 #fj ,plata ,v]de m9e3 #ij ,polk ,c\nty3 #ih porphyritic rocks3 #de1 #he portl& cem5t3 #ea1 #fi1 #hh ,precambrian3 #b1 #c1 #dd1 #de1 #dh1 #eb1 #ec1 #ef1 #eh1 #ei1 #fj1 #fa1 #fc1 #fg1 #gb1 #gd1 #ge1 #gf1 #gi1 #hb1 #he1 #hg1 #ic1 #id1 #ie1 #ig preci\s opal3 #gh ,presidio ,c\nty3 #de1 #di1 #eg1 #fj1 #fb1 #fg1 #gg1 #gh1 #hd1 #he1 #ij1 #ig ,presidio m9e3 #fj1 #ij prop]ties ( m9]als3 #ad pseudomorphs3 #gj1 #hg pulv]ul5t lime/one3 #da1 #fi pumicite3 #ig1 #ih pyramidal cleavage3 #gd pyrite3 #ai1 #bf1 #fj1 #gj1 #hj1 #hg pyrolusite3 #bg1 #gc1 #gd pyrox5e3 #de ,q qu>tz3 #h1 #bj1 #bi1 #cj1 #ca1 #cc1 #cf1 #cg1 #ch1 #dh1 #ea1 #ed1 #ef1 #ei1 #fj1 #fa1 #fh1 #gb1 #gh1 #gi1 #hj1ha1 #hd1 #he1 #hf1 #id agate3 #ba1 #hc1 #hd ame?y/3 #cg1 #hb *alc$ony3 #af1 #ba1 #de1 #gh1 #ha1 #hc1 #hf *]t3 #ai1 #dj1 #ha1 #hd cryptocry/all9e3 #ha1 #hd jasp]3 #ha1 #hd milky3 #hb onyx3 #hd rock cry/al3 #hb rose3 #hb1 #hc smoky3 #hb1 #hc qu>tzite3 #da1 #gd1 #hd1 #hf ,quat]n>y3 #b1 #c1 #ea1 #gi1 #ih quicksilv] 7see also m]cury73 #ej ,quitman ,m\nta9s3 #eg1 #eh1 #fj1 #fb1 #fg1 #hb1 #ij ,r radioactivity3 #ie1 #if ,real ,c\nty3 #di1 #ea ,rec5t3 #b1 #c 8r$ b$s03 #eb r$ o*]3 #fg reef lime/one3 #a1 #ab ,reeves ,c\nty3 #fe1 #he1 #ia ref]5ce books3 #bd1 #ci1 #ajj refraction1 d\ble3 #df rhomboh$ral cleavage3 #df1 #ed rhyolite3 #dj1 #he porphyry3 #da1 #he ,rio ,gr&e3 #hc1 #hd1 #ig rock-- cry/al3 #hb gypsum3 #dj1 #fe id5tification *>ts3 #ci salt3 #dj1 #fe units3 #b rocks1 def9ition (3 #h ,rodda1 ,pet] ,u43 vii rose qu>tz3 #hb1 #hc rosettes3 #fc1 #fd ,ru/l] ,spr+s area3 #ia rutile3 #hb ,s salt 7see also halite73 #dj1 #fe1 #ff domes3 #dc1 #eh1 #fd1 #ff1 #ia1 #ig lakes3 #ff rock3 #dj1 #fe ,salt ,=k ( ! ,brazos ,riv]3 #dc s&3 #da1 #eh1 #gb1 #he1 #ia bla/3 #hf build+3 #he filt]+3 #hf glass3 #he-hf s&/one3 #da1 #eb1 #ee1 #eh1 #ei1 #gb1 #gf1 #ha1 #hd1 #hf ,s&y ,creek3 #fj ,san ,saba ,c\nty3 #gj1 #hh ,santa ,anna3 #hf sat9 sp>3 #fd ,satorsky1 ,cyril3 vii scale1 geologic "t3 #b1 #c sc9tillation c\nt]3 #if s*i/3 #da1 #ef1 #eh1 #gb1 #gc1 #gf1 #ha1 #hg1 #ic act9olite3 #hg graphite3 #fc1 #hg hornbl5de3 #hg mica3 #gf1 #hg talc3 #hg1 #ic s*i/osity3 #hg s*orl3 #ie ,scurry ,c\nty3 #ih s$im5t>y rocks1 def9ition (3 #aj s$im5ts3 #h1 #aa *emical3 #ab sel5ite gypsum3 #fc1 #fd1 #gf s]ies3 #b s]p5t9e3 #cd1 #dj1 #dd1 #ge1 #hg1 #ic s]p5t9ite3 #hg ,sev5 ,he>t ,gap3 #de ,%aft]3 #eg1 #eh1 #fj1 #fg1 #ij ,%aft] ,lake3 #hc %ale3 #ab1 #ac1 #ai1 #dj1 #de1 #gj1 #hg1 #hh oil3 #hh ,%elby1 ,cad] ,a43 vii ,%]idan prospect3 #ec sid]ite3 #gj ,si]ra ,blanca3 #eh1 #fg1 #hb silicifi$ wood 7see also petrifi$ wood73 #bj silt3 #ab1 #he silt/ones3 #ab silv]3 #bf1 #eb1 #eg1 #ei1 #hi glance3 #ij horn3 #ij m9]als3 #hi native3 #bf1 #hi ,silv] ,creek3 #eh s9t]1 calc>e\s3 #df slate3 #ac ,smi? ,c\nty3 #gj smoky qu>tz3 #hb1 #hc soap/one3 #dj1 #ic soils3 #aj ,solit>io uplift3 #db1 #hh ,sonora3 #ah ,cav]ns (3 #ai specific gravity3 #ah1 #ii specul> hematite3 #fg sphal]ite3 #eg ,spill] m9e3 #gd ,sp9dletop salt dome3 #ia ,spr+ ,creek3 #ef /alactites3 #ah1 #ai /alagmites3 #ah1 #ai ,/>r ,c\nty3 #hd1 #ih /atic metamorphism3 #ac ,/onewall ,c\nty3 #eb /reak or p[d] ( m9]als3 #ag /reak plate3 #ag1 #bb ,/reet]3 #dh1 #id /riations3 #ha1 #ie /rontianite3 #di /rontium3 #di sulfur3 #bi1 #cj1 #ca1 #cb1 #cd1 #cf1 #ha1 #ij ,sutton ,c\nty3 #ah1 #ai sy/em3 #b ,t talc3 #bh1 #bi1 #cd1 #hg1 #ic s*i/3 #hg1 #ic ,talc ,rock3 #ic ,taylor ,c\nty3 #de1 #di1 #fj ,t]l+ua area3 #df1 #dg1 #di1 #ej1 #fe ,t]ti>y3 #b1 #c1 #i1 #ba1 #de1 #di1 #ea1 #eb1 #ef1 #eg1 #fj1 #gj1 #gg1 #gh1 #gi1 #hc1 #hd1 #he1 #hf1 #ij1 #ig1 #ih t]razzo-- *ips3 #ee1 #gf floors3 #hh te/s1 *emical 7see *emical te/s7 ?orium3 #hj ,?rall oil field3 #hh "t1 geologic3 #b1 #c t93 #dg topaz3 #cf1 #ch1 #id t\rmal9e3 #cc1 #hb1 #id ,t[n ,m\nta93 #ie ,trans-,pecos area3 #i1 #aj1 #de1 #fj1 #fb1 #fi1 #gh1 #hb1 #hc1 #hd1 #he1 #hg1 #hi1 #ij1 #ih trap rock3 #de trav]t9e3 #df ,travis ,c\nty3 #bj1 #de1 #df1 #di1 #fh1 #fi1 #gj1 #hh tremolite3 #dd1 #ic ,triassic3 #c1 #de1 #hg ,tr9ity ,c\nty3 #ih tufa1 calc>e\s3 #df tw9n$ cry/als3 #df1 #fc tyuyamunite3 #ig ,u ,up%ur ,c\nty3 #gj uranium3 #hj1 #ie1 #if m9]als3 #ie uran9ite3 #ig uranophane3 #ca1 #ie1 #ig ,uvalde ,c\nty3 #de1 #fj1 #hd1 #hh ,v ,valley ,spr+ ,gneiss3 #ei ,val ,v]de ,c\nty3 #de1 #gd1 #ge ,van ,horn area3 #db1 #eb1 #ec1 #eh1 #ei1 #fj1 #ge1 #gf1 #gi1 #he1 #hg1 #ij ,van ,horn ,m\nta9s3 #de1 #ee1 #gf1 #gi1 #ie ,van ,z&t ,c\nty3 #ff v]de antique3 #hh vesicles3 #de vitrophyre3 #dj1 #gg volcanic a%3 #da1 #ig volcanic igne\s rocks1 def9ition (3 #i volcanoes3 #i1 #ig1 #ih ,w ,waco3 #hh wad3 #gc1 #gd ,walk] ,c\nty3 #eb ,w>d ,c\nty3 #ff ,wa%+ton ,c\nty3 #gh1 #hd wea!r+3 #aa ,webb ,c\nty3 #aa1 #hd ,we*es /rata3 #gj ,:>ton ,c\nty3 #ia :ite mica 7see muscovite7 ,wilb>g] ,c\nty3 #ih ,willacy ,c\nty3 #ff ,williamson ,c\nty3 #bj1 #fj1 #fi1 #gj1 #hh ,will[ ,city3 #id wood opal3 #gh wood1 petrifi$3 #bj1 #eb1 #gh1 #hd ,wylie ,m\nta9s3 #ie ,y yell[ copp] ore3 #ec ,yoakum ,c\nty3 #ff ,"y ,c\nty3 #eh yttrium3 #hj ,z ,zapata ,c\nty3 #hc1 #hd ,zavala ,c\nty3 #hf zirconium3 #hj ,transcrib]'s ,notes --,reta9$ publication in=mation f ! pr9t$ edition3 ?is e,book is public-doma9 9 ! c\ntry ( publication4 --,correct$ a few palpable typos4 --,includ$ a transcription ( ! text )9 "s images4 --,9 ! text v]sions only1 text 9 italics is delimit$ by und]scores4 --,add$ a label to "o figure 7to mat* ! ,table ( ,illu/rations74