,,bureau ,,( ,,economic ,,geology ,! ,univ]sity ( ,texas at ,au/9 ,au/91 ,texas #ghgab ,,john ,t4 ,,lonsdale1 ,director ,report ( ,inve/igations--,no4 #db ,texas ,gem/ones ,by ,elb]t ,a4 ,k+1 ,jr4 ,febru>y #aifa ,second ,pr9t+--,febru>y #aifc ,?ird ,pr9t+--,septemb] #aigb ,f\r? ,pr9t+--,m>* #aihc ,fif? ,pr9t+--,augu/ #aiia ,cont5ts ,page ,introduction #e ,prop]ties ( gem/ones #e ,cry/als #g ,cutt+ & poli%+ ( gem/ones #aj ,cabo*on gems #aj ,facet$ gems #ac ,tumbl$ gems #ag ,texas gem/ones #ah ,amb] #ah ,augite #ah ,b]yl #ah ,cele/ite #ai ,diamond #ai ,epidote #ai ,fluorite #bj ,fossil wood #bj ,gadol9ite #ba ,g>net #bb ,jet #bb ,labradorite #bc ,microcl9e #bc ,obsidian #bd ,opal #bd ,pe>l #bd ,qu>tz #be ,cry/all9e v>ieties #be ,ame?y/ #be ,citr9e #be ,rock cry/al #bf ,rose qu>tz #bf ,smoky qu>tz #bf ,cryptocry/all9e v>ieties #bg ,*alc$ony #bg ,agate #bg ,agatiz$ wood #bg ,c>nelian #bg ,jasp] #bg ,sanid9e #bh ,sp9el #bh ,tektite 7b$iasite7 #bh ,topaz #bi ,t\rmal9e #cj ,turquoise #ca ,gloss>y #cb ,select$ ref]5ces #cd ,index #da ,illu/rations ,figures-- ,page #a4 ,typical cry/al =m ( ?ree common ,texas gem/ones #i #b4 ,v>iations ( ! cabo*on cut #aj #c4 ,diamond saw #aa #d4 ,cabo*on prop]ly atta*$ to dop-/ick #ab #e4 ,cabo*ons at v>i\s /ages ( cutt+ & poli%+ #ab #f4 ,nom5clature ( ! /&>d ,am]ican brilliant cut #ac #g4 ,facet table #ad #h4 ,gr9d+ ! table facet on a r\gh /one #ae #i4 ,/one dopp$ to table facet #ae #aj4 ,pre=m$ /one dopp$ to table facet #af #aa4 ,prop] sequ5ce ( cutt+ ( ! pavilion facets #af #ab4 ,prop] plac+ ( pavilion girdle facets #ag #ac4 ,prop] sequ5ce ( cutt+ ( cr[n facets #ag #ad4 ,common cry/al =m ( ,travis ,c\nty cele/ite #ai #ae4 ,common cry/al =m ( fluorite #bj #af4 ,cry/al faces on microcl9e specim5 %[n 9 ,plate ,,iii #bc #ag4 ,common cry/al =m ( sp9el #bh #ah4 ,cry/al faces on topaz cry/al %[n 9 ,plate ,v #bi #ai4 ,cross section ?r\gh irregul>ly color$ /one #cj #bj4 ,common cry/al =m ( ,llano ,c\nty t\rmal9e #ca ,plates-- ,page ,i4 ,a1 ,gem-quality cele/ite cry/als f ,travis ,c\nty4 ,b1 ,opaliz$ wood f ! ,texas ,gulf ,coa/al ,pla9 #ce ,,ii4 ,a1 ,gem-quality g>net cry/als & facet$ gem f ,gillespie ,c\nty4 ,b1 ,labradorite f ,brew/] ,c\nty #cf ,,iii4 ,a1 ,p9k microcl9e cry/al4 ,b1 ,smoky qu>tz4 ,bo? f ,burnet ,c\nty #cg ,,iv4 ,poli%$ agate f gravels ( ! ,rio ,gr&e ne> ,zapata1 ,zapata ,c\nty #ch ,v4 ,a1 ,texas tektites 7b$iasites74 ,b1 ,topaz cry/al f a pegmatite dike ne> ,/reet]1 ,mason ,c\nty #ci ,,vi4 ,a1 ,topaz f /ream gravels ne> ,/reet]1 ,mason ,c\nty4 ,b1 ,t\rmal9e cry/als 9 s*i/ f ,llano ,c\nty #dj ,table #a4 ,prop]ties ( "s common ,texas gem m9]als #h ,texas ,gem/ones ,,elb]t ,a4 ,,k+1 ,,jr4 ,,introduction ,?r\gh\t hi/ory man has s\ght /ones & m9]als = p]sonal adornm5t & ornam5tation4 ,/ones & m9]als t are suffici5tly beautiful1 durable1 & r>e are kn[n z gem/ones4 ,a gem/one ) only "o ( ^! qualities is less desirable ?an "o ) all ?ree4 ,= example1 a /one ) ri* color b n suffici5tly durable to )/& daily we> 9 r+s f9ds little favor z a gem/one except 9 broo*es or p9s :]e ! /one is relatively safe f abrasion4 ,likewise1 a /one t is beautiful & durable may be ( little int]e/ z a gem/one because x is commonly f\nd 9 great quantities4 ,to be valu$ highly1 gem/ones mu/ be beautiful to ! eye1 durable en\gh to )/& we>1 & r>e en\gh s t !y are n easily obta9$4 ,prop]ties ( ,gem/ones ,! beauty ( gem/ones is mo/ly dep5d5t on _! color1 diaphaneity1 brilliancy1 lu/]1 & fire4 ,any "o or a comb9ation ( ^! prop]ties r5d] /ones desirable z gems4 ,color is v important 9 _m gem/ones4 ,! color ( transp>5t v>ieties %\ld be di/9ct en\gh to be pleas+ to ! eye1 yet n s d>k z to appe> black or opaque4 ,x is g5]ally m desirable t ! gem/one be ( ev5 color & n appe> 8pat*y0 or 8/reak$40 ,h[ev]1 "s opaque or transluc5t /ones su* z agate owe _! popul>ity *iefly to ! v>iety ( colors & designs )9 a s+le piece4 ,"s transp>5t gem/ones exhibit diff]5t colors :5 view$ 9 diff]5t directions4 ,= example1 "s f9e blood-r$ rubies appe> br[ni% :5 view$ 9 a p>ticul> direction4 ,! gem/one %\ld be cut s t its f9e/ color is mo/ prom95tly display$4 ,?is ability ( "s gem/ones to exhibit diff]5t colors :5 view$ 9 diff]5t directions is call$ pleo*roism4 ,diaphaneity is ! relative ability ( /ones to transmit light4 ,diaphaneity is describ$ by t]ms su* z transp>5t1 transluc5t1 & opaque4 ,transp>5cy is highly desirable 9 /ones su* z diamond t are commonly facet-cut to reflect light4 ,! gem/one %\ld be wat] cle> & free f inclusions & cracks s t x transmits light freely1 b !re are /ones t d n exhibit ?is prop]ty t are priz$ z gem/ones4 ,= example1 turquoise may appe> to be completely opaque & n transmit any light1 b x is s\ght = its f9e blue color4 ,! brilliancy ( gem/ones is l>gely dep5d5t on _! index ( refraction4 ,! index ( refraction is a measure ( ! ability ( a cut gem/one to 8b5d0 light rays & reflect !m f ! bottom facets back ?r\gh ! top ( ! /one4 ,( c\rse1 brilliancy is n not$ 9 opaque or fa9tly transluc5t /ones4 ,! index ( refraction ( gem/ones is express$ num]ically4 ,air is ! ref]5ce m$ium & is assign$ an index ( refraction ( #a4jj4 ,o!r sub/ances are assign$ values relative to t ( air1 = example1 wat]1 #a4cc2 topaz1 #a4fb2 diamond1 #b4db4 ,! high] ! index ( refraction1 ! m brilliant w be ! gem/one if x is prop]ly cut & poli%$4 ,lu/] is ! appe>ance ( ! m9]al on a fre% surface 9 reflect$ light2 x is divid$ into two major categories1 metallic & non-metallic4 ,mo/ gem/ones h non-metallic lu/] & are describ$ by t]ms su* z vitre\s or glassy1 res9\s1 waxy1 greasy1 & pe>ly4 ,! fire1 or ability ( gem/ones to %[ fla%es ( diff]5t colors ( light1 is dep5d5t ^u a prop]ty call$ disp]sion4 ,! am\nt ( disp]sion is ! ext5t to :i* ! gem/one is able to sep>ate ord9>y :ite light into its compon5t colors4 ,! disp]sion ( gem/ones c also be express$ num]ically b = purposes ( ?is publication w be ref]r$ to z l[1 mod]ate1 or high4 ,diamond is a common gem/one t has high disp]sion4 ,a gem/one's durability is prim>ily dep5d5t ^u its h>dness4 ,! ,mohs scale ( h>dness1 giv5 bel[1 is mo/ commonly us$ = gem/ones & o!r m9]als4 ,mohs ,scale ( ,h>dness #a4 ,talc #b4 ,gypsum #c4 ,calcite #d4 ,fluorite #e4 ,apatite #f4 ,or?oclase feldsp> #g4 ,qu>tz #h4 ,topaz #i4 ,corundum #aj4 ,diamond ,on ?is scale1 ! high] numb]s are ! h>d] m9]als4 ,mohs is a relative1 n an absolute scale4 ,!re=e1 x %\ld n be assum$ t diamond is t5 times h>d] ?an talc because actually diamond is v _m t5s ( times h>d] ?an talc4 ,h[ev]1 a p>ticul> m9]al is h>d] ?an any o!r m9]al ) a less] numb]1 & ! scale is v conv5i5t to use4 ,gem/ones m\nt$ 9 r+s %\ld h a h>dness ( at lea/ sev5 on ! ,mohs scale1 or ! /ones may become scuff$ & scrat*$ aft] a relatively %ort p]iod ( we>4 ,gem/ones m\nt$ 9 p9s & broo*es c be ( s(t] mat]ial z !y are n usually subject$ to abrasion & r\gh treatm5t4 ,! t5d5cy ( "s m9]als to split ) relative ease 9 p>ticul> directions along planes is call$ cleavage4 ,cleavage is also a factor det]m9+ ! durability ( gem/ones4 ,"s gem/ones d n exhibit ?is t5d5cy at all1 :]eas o!rs cleave 9 sev]al directions4 ,! numb] ( cleavages is always ! same 9 any "o m9]al1 & ! direction ( cleavages is con/ant 9 relation to ! cry/al /ructure ( any "o m9]al or gem/one4 ,x is app>5t t ( /ones hav+ ! same h>dness1 ! ones lack+ cleavage or hav+ ! less] numb] ( good cleavage directions are ! mo/ durable4 ,"s /ones1 su* z jade & agate1 owe _! durability to _! compact fibr\s /ructure1 :i* makes !m v t\gh & durable ev5 ?\gh !y are n especially h>d4 ,sev]al o!r prop]ties ( gem/ones1 al?\gh n always contribut+ to ! beauty or desirability ( gem/ones1 are useful 9 id5tify+ uncut specim5s4 ,/reak is ! color ( ! m9]al :5 f9ely p[d]$ or1 = s(t] m9]als1 ! color obta9$ by rubb+ ! m9]al aga9/ a piece ( unglaz$ porcela9 or tile4 ,! color ( a m9]al's /reak is commonly diff]5t f ! unp[d]$ specim54 ,fracture is ! k9d ( surface obta9$ :5 ! m9]al is brok5 9 a direction t is n a cleavage direction4 ,fracture surfaces are describ$ by su* t]ms z con*oidal 7l ! fracture ( glass71 subcon*oidal1 spl9t]y1 ev51 & unev54 ,t5acity is ! resi/ance ( a m9]al to breakage4 ,brittle m9]als break relatively easily on impact4 ,malleable m9]als1 su* z gold1 may be flatt5$ "u a hamm] into v ?9 %eets )\t break+4 ,sectile m9]als may be cut ) a knife )\t p[d]+4 ,mo/ gem/ones1 ev5 diamond1 are brittle4 ,x is only natural to value mo/ ^? gem/ones t are n common or easy to obta94 ,em]ald owes its long/&+ popul>ity to its f9e gre5 color1 b t\rmal9e is sometimes f\nd 9 colors t v closely approa* t ( em]ald & yet sells = consid]ably less because x is s mu* m common4 ,r>ity is n ! only factor affect+ ! value ( gem/ones4 ,fre$om f int]nal imp]fections1 quality ( cutt+1 color1 & size mu/ also be consid]$ 9 cut & poli%$ gem/ones4 ,int]nal imp]fections1 su* z inclusions & cracks1 detract f ! appe>ance ( gem/ones & int]f]e ) ! passage ( light betwe5 ! facets2 consequ5tly1 gem/ones conta9+ ^! imp]fections are n valu$ z highly z ^? )\t !m4 ,poor cutt+ or poli%+ detract f ! beauty & ?us f ! value ( gem/ones4 ,unpopul> or poor color commonly causes gem/ones to be less valuable4 ,ri* gre5 em]alds are exce$+ly priz$1 :]eas v pale gre5 em]alds are relatively inexp5sive4 ,diamonds t h ! lea/ h9t ( yell[ are nev] valu$ z highly z pure colorless1 p9k1 or blue /ones4 ,few p]sons f9d ! yell[i% color attractive1 unless x is a vivid can>y yell[4 ,size is important 9 det]m9+ ! value ( gem/ones b n z important z p]fection4 ,a badly flaw$ gem/one ( l>ge size may be wor? only a slight fraction ( ! value ( a small] p]fect "o4 ,gem/one size is usually measur$ 9 c>ats1 a unit ( weight1 al?\gh millimet] size is sometimes us$4 ,five c>ats is equal to #a gram & approximately #bh grams is equal to #a ounce avoirdupois4 ,"o "o-hundr$? 7#j4ja7 ( a c>at is call$ a po9t1 & ?is t]m is (t5 us$1 especially p]ta9+ to v small gem/ones4 ,! t]m us$ to comp>e ! relative weights ( m9]als & gem/ones is specific gravity1 :i* is express$ num]ically 9 relation to wat]4 ,wat] is assign$ ! value ( #a4jj4 ,!re=e1 at a giv5 temp]ature a gem/one hav+ a specific gravity ( #b4jj is twice z heavy z an equal volume ( wat]4 ,a #a-;c>at sapphire 7specific gravity ab\t #d4jj7 w be small] ?an a #a-;c>at ame?y/ 7specific gravity ab\t #b4fe7 because ! heavi] mat]ial w occupy less volume to h ! same weight4 ,a summ>y ( prop]ties helpful 9 id5tification ( common ,texas gem m9]als is giv5 9 ,table #a4 ,comp>atively rec5tly 9 ! hi/ory ( gem/ones1 man has succe$$ 9 ! production ( syn!tic gems t h prop]ties closely approa*+ ^? ( _m natural gem/ones4 ,to ! untra9$ eye "s syn!tic gems may appe> id5tical to natural /ones1 b syn!tic gems c be detect$ ) little difficulty by a prop]ly equipp$ exp]t4 ,al?\gh mo/ syn!tic gems are inexp5sive1 _! manufacture has n adv]sely affect$ ! value ( natural gem/ones b in/ead has increas$ ! dem& = f9e natural gems4 ,cry/als ,gem/ones t h an ord]ly int]nal molecul> arrangem5t are ref]r$ to z cry/all9e4 ,?is int]nal ord] is commonly reflect$ 9 ! ext]nal %ape ( 8r\gh0 or uncut gem/ones4 ,! resultant %ape is a polyh$ral solid b\nd$ by planes & call$ a cry/al4 ,well-=m$ cry/als are =m$ 9 nature only "u relatively ideal conditions ( temp]ature1 pressure1 & space4 ,! specific temp]atures & pressures involv$ v>y ) diff]5t m9]als1 b mo/ cry/als ne$ space 9 :i* to =m s t _! 8gr[?0 is n impair$ by surr\nd+ rocks & m9]als4 ,h[ev]1 "s m9]als1 su* z g>net & t\rmal9e1 c gr[ 9 metamorphic rocks by recry/allization ( m9]als 9 ! metamorphic rocks4 ,! size ( cry/als v>ies f microscopic to t5s ( feet4 ,any "o m9]al usually has "o or two typical cry/al =ms or arrangem5ts ( plane surfaces t aid greatly 9 ! id5tification ( ! m9]al :5 x occurs 9 good cry/als 7fig4 #a74 ,frequ5tly gem/ones are f\nd z abrad$ /ream-roll$ pebbles1 fragm5ts1 or masses t d n %[ cry/al =m4 ,cry/als ( ! same m9]al f diff]5t locations commonly %[ some:at diff]5t cry/al =ms ow+ to slight diff]5ces 9 composition or conditions ( =mation4 ,m9]alogi/s & cry/allograph]s classify cry/als by ! symmetry t !y exhibit4 ,! cry/al sy/ems are 7#a7 isometric or cubic1 7#b7 tetragonal1 7#c7 hexagonal1 7#d7 or?orhombic1 7#e7 monocl9ic1 & 7#f7 tricl9ic4 ,a complete description ( ! classification ( cry/als c be f\nd 9 almo/ any m9]alogy text 7see ,select$ ,ref]5ces1 p4 #cd74 ,table #a4 ,prop]ties ( "s common ,texas gem m9]als4 ,,m9]al ,,composition ,,h>dness ,,specific ,,index ,,( ,,common ,,gravity ,,refraction ,,colors ,,9 ,,texas ,amb] fossil res9 #b4j-b4e #a4je-a4aj ab\t #a4ed br[n1 yell[ ,augite ,ca,mg,si,o #e4j-f4j #c4b-c4f #a4fj-a4ga gre5i% br[n1 black ,b]yl ,be,al7,si,o7 #g4e-h4j #b4fc-b4hj #a4ef-a4fj pale blue1 colorless1 gre5i% ,cele/ite ,sr,s,o #c4j-c4e #c4ie-c4ih #a4fb-a4fc colorless1 blue ,epidote ,h,ca7,al1 #f4j-g4j #c4be-c4ej #a4gb-a4gg yell[i% ,fe7,si,o gre51 br[ni% gre5 ,fluorite ,ca,f #d4j #c4j-c4be #a4dcd colorless1 violet1 yell[1 gre5 ,g>net ,fe,al7,si,o7 ab\t #g4e #d4be ab\t #a4hc r$1 deep 7,alm&ite7 r$1 br[ni% r$ ,labradorite ,na,al,si,o #ej to #f4j-f4e ab\t #b4f ab\t #a4ef yell[i%1 #cj ,ca,al,si,o #ej grayi% to #gj ,microcl9e ,k,al,si,o #f4j-f4e #b4ed-b4eg #a4eb-a4ec p9k1 r$1 blui%1 gre5i%1 :ite ,obsidian volcanic glass #e4j-e4e #b4c-b4e #a4de-a4ec d>k gray1 black1 br[ni% ,opal ,si,on,h,o #e4e-f4e #a4i-b4c #a4dc :ite1 p9k1 blui%1 br[n1 gray ,qu>tz ,si,o #g4j #b4fe-b4ff #a4edd-a4eec colorless1 7,cry/all9e7 violet1 yell[1 br[n ,tektite natural glass #e-f #b4cc-b4dd #a4dh-a4eb d>k br[n1 7,b$iasite7 gre5i% br[n ,topaz ,al7,f,,oh7,si,o #h4j #c4d-c4f #a4fj-a4fc colorless1 blui%1 sky blue ,t\rmal9e ,h,al7,b,,oh7,si,o #g4j-g4e #b4ih-c4bj #a4fb-a4fd black1 d>k br[n ,"s gem/ones1 su* z opal & obsidian1 nev] occur z cry/als ow+ to a lack ( int]nal /ructural ord]4 ,su* gem/ones are t]m$ amorph\s1 or )\t =m4 ,amorph\s gem/ones mo/ly occur 9 nature z irregul> lumps or masses1 cavity fill+s1 or ve9s4 ,illu/ration3 ,fig4 #a4 ,typical cry/al =m ( ?ree common ,texas gem/ones4 ,,g>net ,,t\rmal9e ,,qu>tz ,,cutt+ ,,& ,,poli%+ ,,( ,,gem/ones ,!re are two types ( widely us$ gem/one cuts4 ,opaque or figur$ gem/ones are usually cut ) a r\nd$ upp] surface & a flat or r\nd$ back4 ,a /one cut 9 ?is fa%ion is t]m$ a cabo*on or is said to be cabo*on cut4 ,!re are sev]al v>iations ( ?is mode ( cutt+ 7fig4 #b74 ,preci\s opal1 agate1 jade1 /> sapphire1 & fossil wood are "s ( ! /ones t are cut mo/ly z cabo*ons4 ,transp>5t gem/ones are usually cut ) _m plane poli%$ surfaces4 ,su* /ones are call$ facet$1 & ! process ( cutt+ & poli%+ ^! /ones is call$ facet+4 ,em]ald1 diamond1 topaz1 & g>net are examples ( gem/ones t are commonly se5 z facet$ /ones4 ,illu/ration3 ,fig4 #b4 ,v>iations ( ! cabo*on cut4 ,left to "r3 d\ble cabo*on2 flat cabo*on2 simple cabo*on2 holl[ cabo*on4 ,! cutt+ ( gem/ones1 al?\gh sometimes t$i\s & "t consum+1 is n especially difficult or complex4 ,h[ev]1 l mo/ arts & crafts1 te*nique & ability %\ld improve ) practice & exp]i5ce4 ,!re are curr5tly _m amateur gem cutt]s 9 ,texas4 ,a complete set ( equipm5t necess>y to cut cabo*on /ones may be pur*as$ = z little z #ej4jj or #fj4jj4 ,mo/ amateur cabo*on cutt]s h equipm5t t co/ less ?an #ajj4jj :i* enables !m to d v f9e "w on _m gem mat]ials4 ,facet cutt+ requires m precise equipm5t1 & a complete array ( su* usually co/s m ?an #ajj4jj1 al?\gh less exp5sive equipm5t c be obta9$4 ,! beg9n+ gem cutt] or lapid>y :o is will+ to assemble & make "s ( 8 own equipm5t c r$uce 8 initial exp5ses consid]ably4 ,cabo*on ,gems ,! proc$ures li/$ h]e9 = gem cutt+ d n apply to all gem/ones4 ,/ones t are especially brittle1 s(t1 or difficult to poli% require additional proc$ures or special te*niques4 ,_m lapid>ies may deviate f ^! proc$ures4 ,"s ( ! /eps ( cutt+ & poli%+ are m]ely matt]s ( p]sonal op9ion & v>y some:at f cutt] to cutt]4 ,!re are sev]al detail$ texts on ! art ( gem cutt+2 ! descriptions h]e9 are design$ to give ! read] only a g5]al idea ( ! proc$ures & te*niques involv$4 ,! cutt+ & poli%+ ( cabo*ons require sev]al /eps4 ,! initial /ep is saw+4 ,assum+ t ! r\gh gem mat]ial is l>ge en\gh to be saw$ 7l>g] ?an ab\t half an in* 9 diamet]71 x is clamp$ into ! c>riage ( a diamond saw 7fig4 #c7 & cut into slices ab\t -in* ?ick4 ,! blade ( ! saw is mild /eel t has be5 impregnat$ ) diamond du/ ar\nd ! edge1 h5ce ! "n diamond saw4 ,! blade is rotat$ rapidly1 & ! mat]ial to be cut is 8f$0 to ! blade by a slid+ c>riage on :i* ! gem mat]ial is clamp$4 ,! extreme h>dness ( ! diamond du/ 9 ! edge ( ! blade enables ! saw to cut ?r\gh sev]al in*es ( gem mat]ial 9 a few m9utes4 ,! l[] portion ( ! saw blade is imm]s$ 9 a mixture ( k]os5e & oil1 & ! rotat+ saw blade c>ries ) x "s ( ! k]os5e-oil mixture2 ?is acts z a coolant & lubricant = bo? ! saw blade & ! mat]ial be+ cut4 ,)\t ?is lubricant1 ! heat g5]at$ by saw+ w\ld %att] mo/ gem mat]ials & also damage ! saw blade4 ,z ?is 8slic+0 or saw+ ( ! mat]ial usually takes sev]al m9utes1 a weight & pulley are g5]ally us$ to give ! gem mat]ial ! necess>y pressure aga9/ ! saw blade4 ,:5 cut ?r\gh1 ! 8slab0 ( gem mat]ial falls into ! k]os5e-oil mixture at ! bottom ( ! saw or onto a special plat=m t cu%ions its fall4 ,illu/ration3 ,fig4 #c4 ,diamond saw4 ,motor ,clamp ,diamond-*>g$ blade ,c>riage ,/one ,weight ,aft] be+ saw$1 ! slab ( gem mat]ial is exam9$1 & ! location & size ( ! /ones to be cut f ! slab are det]m9$4 ,! desir$ outl9e ( ! %ape ( ! gem to be cut is m>k$ on ! slab ) a po9t$ piece ( alum9um rod2 ord9>y p5cil m>ks are n us$ because !y we> away too quickly 9 ! cutt+ process4 ,once ! area f :i* ! gem is to be cut has be5 select$ & ! outl9e ( ! gem/one has be5 m>k$ on ! slab1 ! excess mat]ial is trimm$ away by a small] diamond saw kn[n z a trim-saw4 ,9 "s slabs ! excess mat]ial c be brok5 & 8nibbl$0 away ) a /rong pair ( pli]s4 ,! rema9+ portion ( ! /one is usually held by h& & gr\nd to ! desir$ %ape us+ ! previ\sly scrib$ m>k z a guide4 ,?is is done us+ a relatively co>se-gra9$ 7ab\t #aej grit7 specially made c>borundum gr9d+ :eel4 ,n[ t ! desir$ outl9e has be5 obta9$1 ! /one is firmly affix$ to a sl5d] wood5 or holl[ alum9um dop-/ick 7fig4 #d74 ,! process :]eby ! /one is atta*$ to ! dop-/ick ) a specially comp\nd$ jewel]'s wax is call$ dopp+4 ,! dop-wax is heat$ ov] an alcohol lamp or c&le flame until x is s(t & pliable & is !n spread ar\nd on ! end ( ! dop-/ick & =m$ into a mass ab\t ! "r size & %ape to fit ! back ( ! gem/one4 ,! /one is likewise heat$1 & ! wax is appli$ to ! back ( ! /one :ile bo? wax & /one are hot4 ,^u cool+1 ! wax firmly fixes ! /one to ! dop-/ick4 ,! dop-/ick all[s ! lapid>y to h firm control ( ! /one dur+ all lat] /ages ( cutt+ & poli%+4 ,illu/ration3 ,fig4 #d4 ,cabo*on prop]ly atta*$ to dop-/ick4 ,,cabo*on ,,dop-,,wax ,,dop-,,/ick ,! top ( ! dopp$ gem/one is work$ aga9/ ! co>se c>borundum gr9d+ :eel until x is a r\gh approximation ( ! desir$ %ape4 ,! /one is !n work$ aga9/ a mu* f9]-gra9$ 7ab\t #bbj grit7 gr9d+ :eel to remove ! irregul>ities left by ! co>se gr9d+ & to fur!r smoo? & %ape ! surface ( ! gem/one4 ,at all times :ile gr9d+1 a small fl[ ( wat] %\ld be direct$ on ! gr9d+ :eel to keep ! /one cool4 ,gr9d+ on ! /one = ev5 a few m9utes )\t cool+ may result 9 ! %att]+ ( ! gem/one because ( heat creat$ by friction ( ! /one aga9/ ! gr9d+ :eel4 ,if ! lapid>y keeps ! surface ( ! gr9d+ :eel wet1 !re is little *ance ( damag+ mo/ gem mat]ials4 ,! next phase ( cabo*on cutt+ & poli%+ is s&+4 ,! gem/one is work$ aga9/ two s&+ drums ( diff]5t grit size4 ,?is s&+ c be done ) ! s&pap] surface ei!r wet or dry1 z ne$$ or z pref]r$ by ! lapid>y4 ,h[ev]1 great c>e %\ld be ex]cis$ dur+ s&+ s t ! /one is n ov]heat$4 ,ov]heat+ c easily occur :e!r ! s&pap] is us$ wet or dry4 ,z 9 gr9d+1 s&+ is fir/ done on co>s] grit pap] 7ab\t #cjj grit7 & la/ on f9] pap] 7ab\t #fjj grit74 ,x is 9 ! s&+ process t ! fir/ h9t ( poli% is not$ on ! surface ( ! /one4 ,aft] s&+1 ! gem/one %\ld h p]fect =m ) no surface irregul>ities1 a v f9ely textur$ surface1 & only v m9or scrat*es left f s&+4 ,! gem/one is n[ ready to be poli%$4 ,illu/ration3 ,fig4 #e4 ,cabo*ons at v>i\s /ages ( cutt+ & poli%+4 ,left to "r3 trimm$ f slab3 gr\nd to outl9e2 aft] r\gh gr9d+2 aft] s&+2 poli%$4 ,at ?is po9t ! proc$ure dep5ds on ! nature ( ! gem/one be+ poli%$4 ,mo/ gem mat]ials are work$ aga9/ a buff+ :eel t is impregnat$ or saturat$ ) a mixture ( "s poli%+ comp\nd & wat]4 ,a s(t felt buff+ :eel ) c]ium oxide z ! poli%+ ag5t is us$ = _m mat]ials4 ,! mixture ( c]ium oxide & wat] is usually appli$ to ! buff+ :eel ) a small bru%4 ,! lapid>y %\ld once m be c>eful n to ov]heat ! /one4 ,if ! /one becomes too hot to hold to ! und]side ( ! cutt]'s wri/1 x %\ld be p]mitt$ to cool = a few seconds be=e cont9u+4 ,aft] poli%+ on ! buff+ :eel1 ! gem/one %\ld h a f9e1 high poli% & be free ( any scrat*es or surface irregul>ities4 ,! f9i%$ gem/one is remov$ f ! dop-/ick by heat+ ! dop-wax & pull+ ! /one loose4 ,any excess wax t h>d5s aga9 be=e x c be remov$ f ! /one by h& c be dissolv$ away by rubb+ ) an acetone-soak$ clo?4 ,figure #e illu/rates ! desir$ appe>ance ( ! gem/one at ! end ( ea* ( ! /eps ( cutt+ & poli%+4 ,facet$ ,gems ,! pr9ciples involv$ 9 facet+ are ab\t ! same z ^? 9 ! cutt+ ( cabo*ons1 b ! equipm5t & te*nique are consid]ably diff]5t4 ,! equipm5t requir$ = ! facet cutt+ ( gem/ones is built into or atta*$ to a small specially con/ruct$ table 7fig4 #g71 & ! unit is commonly call$ a facet table4 ,mo/ facet$ gem/ones are cut to obta9 ! l>ge/ flawless /one possible f ! r\gh mat]ial4 ,!re=e1 "o ( ! fir/ & mo/ important /eps = ! lapid>y is to decide h[ ! /one is to be cut f ! r\gh cry/al or pebble4 ,! colors t c be obta9$ f ! gem/one mu/ also be consid]$1 & ! cutt+ ( ! /one ori5t$ s t its be/ color is display$4 ,! lapid>y also selects ! ori5tation ( ! /one 9 relation to ! cleavage or cleavages4 ,x is difficult or impossible to poli% facets ( gem/ones t are cut p>allel to a good cleavage direction4 ,illu/ration3 ,fig4 #f4 ,nom5clature ( ! /&>d ,am]ican brilliant cut4 ,,top ,,view ,,side ,,view ,/> facet ,cr[n ma9 facet ,cr[n girdle facet ,pavilion girdle facet ,pavilion ma9 facet ,,table ,,cr[n ,,girdle ,,pavilion ,,culet ,,bottom ,,view ,once ! ori5tation ( ! gem/one to be cut f ! r\gh mat]ial has be5 det]m9$1 ! /one is dopp$ onto a special metal dop-/ick t fits into ! *uck ( ! facet head4 ,! *uck is tight5$ s t ! position ( ! /one on ! end ( ! arm ( ! facet head is firmly fix$1 & ! facet head is adju/$ s t ! fir/ facet t is cut is ! horizontal1 top facet ( ! /one or table facet 7fig4 #f74 ,! table facet is cut by gr9d+ ! gem/one on a flat cutt+ lap t is diamond impregnat$ 7fig4 #h74 ,by m9or adju/m5ts ( ! facet head1 ! lapid>y c precisely control ! location ( ! table facet4 ,z soon z ! table facet has be5 gr\nd to ! prop] size1 ! cutt+ lap is remov$ f ! lap plate1 & ! poli%+ lap is secur$ 9 place4 ,_m diff]5t k9ds ( poli%+ laps & poli%+ comp\nds may be us$ dep5d+ on ! prop]ties ( ! mat]ial be+ poli%$4 ,h[ev]1 "o lap & "o poli%+ comp\nd are usually suffici5t = ea* gem v>iety4 ,aft] ! poli%+ lap is secur$ to ! lap plate1 ! lapid>y adju/s ! facet head s t ! /one is 9 exactly ! same position relative to ! lap t x 0 dur+ ! cutt+ ( ! table facet4 ,! poli%+ lap is run wet or damp ) wat]1 z is ! cutt+ lap1 & small am\nts ( ! poli%+ comp\nd are appli$ to ! surface ( ! lap :ile ! facet is be+ poli%$4 ,! m9or scrat*es left by ! cutt+ process are gradually remov$1 & a f9e lu/r\s poli% develops on ! facet4 ,x is especially important to take c>e 9 a*iev+ a p]fect poli% on ! table facet1 z ?is facet occupies a l>ge area ( ! cr[n ( ! gem/one4 ,:5 ! cutt+ & poli%+ ( ! table facet are complet$1 ! gem/one is /ill r\gh or uncut 9 all portions except = ?is s+le1 l>ge1 poli%$ surface4 ,illu/ration3 ,fig4 #g4 ,facet table4 ,wat] ,light ,adju/+ r+ ,po/ ,arm ,*uck ,/one ,abrasives ,,diamond ,,du/ ,,calcium ,,oxide ,,l&e-,a ,illu/ration3 ,fig4 #h4 ,gr9d+ ! table facet on a r\gh /one4 ,,*uck ,,dop-,,/ick ,,dop-,,wax ,,/one ,,lap ,! gem/one is !n remov$ f ! dop-/ick by melt+ ! dop-wax & is dopp$ once m s t ! plane ( ! poli%$ table facet is p]p5dicul> to ! axis ( ! *uck & arm ( ! facet head 7fig4 #i74 ,great c>e %\ld be tak5 by ! lapid>y to insure t ! table ( ! /one is exactly p]p5dicul> to ?is axis1 or ! prop] plac+ ( ! lat] facets on ! /one may become v difficult4 ,illu/ration3 ,fig4 #i4 ,/one dopp$ to table facet4 ,,table ,,facet ,,dop-,,wax ,,/one ,,dop-,,/ick ,once ! /one has be5 prop]ly dopp$ to ! table facet1 ! lapid>y is ready to proce$ ) ! cutt+ ( ! outl9e ( ! /one4 ,if x is to be a brilliant cut1 ! /one is gr\nd p]fectly r\nd 9 outl9e2 if x is to be an em]ald or /ep cut1 x is %ap$ s t x is squ>e or rectangul> 9 outl9e4 ,?is process is call$ pre=m+4 ,! arm ( ! facet head is l[]$ on ! po/ until x is horizontal1 & ! /one is work$ aga9/ ! cutt+ lap until ! desir$ %ape is obta9$4 ,:5 ! pre=m+ process is complet$1 ! /one %\ld h ! desir$ outl9e ( ! f9i%$ gem 7fig4 #aj74 ,illu/ration3 ,fig4 #aj4 ,pre=m$ /one dopp$ to table facet4 ,,dop-,,wax ,,/one ,,dop-,,/ick ,! lapid>y is n[ ready to proce$ ) ! cutt+ ( ! pavilion ( ! /one4 ,! arm ( ! facet head is rais$ to ! prop] angle = cutt+ ! ma9 pavilion facets4 ,! angle at :i* ! ma9 facets are cut is v critical 9 det]m9+ ! beauty ( ! f9i%$ /one4 ,! requir$ angle at :i* ^! facets mu/ be cut v>ies ) ! refractive indices ( ! diff]5t v>ieties ( gem m9]als4 ,if ! facets are n cut at exactly ! prop] angle1 light ent]+ ! top or cr[n ( ! gem/one c pass completely ?r\gh ! /one1 in/ead ( be+ reflect$ back out ( ! cr[n facets4 ,! result is a dull1 lifeless /one t appe>s to h a 8hole0 or 8fi%-eye0 9 ! c5t]4 ,/ones t are cut 9 ?is mann] are greatly r$uc$ 9 value4 ,! angle at :i* ! facets are cut is controll$ by ! adju/m5t ( ! height ( ! arm ( ! facet head on ! po/4 ,! lapid>y w cont9ually adju/ ?is height1 because ! angle betwe5 ! arm & ! surface ( ! lap *anges slightly z ! facet is gr\nd d[n to its prop] place & size4 ,illu/ration3 ,fig4 #aa4 ,prop] sequ5ce ( cutt+ ( ! pavilion facets4 ,left to "r3 f\r ma9 facets2 all eight ma9 facets2 half ( ! pavilion girdle facets2 complet$ pavilion4 ,! /&>d ,am]ican brilliant cut w be us$ z an example ( facet cutt+4 ,proc$ure = all o!r cuts is ess5tially ! same to ?is po9t4 ,aft] ! eight ma9 pavilion facets h be5 cut1 ! cutt+ angle is *ang$ a few degrees1 ! arm ( ! facet head rotat$ slightly1 & ! sixte5 pavilion girdle facets or 8skill0 facets1 z !y are (t5 call$1 are cut 7fig4 #aa74 ,! pavilion girdle facets %\ld meet exactly 9 ! c5t] ( ! ma9 facets at ! girdle ( ! /one4 ,! pavilion girdle facets %\ld nei!r ov]lap1 nor %\ld !re be any space betwe5 !m 7fig4 #ab74 ,aft] ! pavilion girdle facets are cut1 ! cutt+ ( ! pavilion ( ! gem/one is complet$4 ,! facets are !n poli%$ on ! poli%+ lap at ! same angles & 9 ! same ord] z !y 7 cut1 & ! pavilion ( ! gem is completely f9i%$4 ,! /one is !n remov$ f ! dop-/ick by melt+ ! dop-wax & is re-dopp$ to ! pavilion facets s t ! cr[n ( ! /one is n[ expos$ = cutt+4 ,be=e ! lapid>y proce$s ) ! cutt+ ( ! cr[n1 x is necess>y t ! /one be p]fectly c5t]$ on ! dop-/ick & t ! plane ( ! table facet be p]p5dicul> to ! dop-/ick & to ! axis ( ! arm ( ! facet head4 ,! eight ma9 facets are cut fir/1 ) num]\s adju/m5ts be+ made by ! lapid>y to insure t ! prop] angle is ma9ta9$ 7fig4 #ac74 ,!n ! cutt+ angle is *ang$ a few degrees1 ! arm ( ! facet head rotat$ slightly1 & ! cr[n girdle facets are cut4 ,! cr[n girdle facets are plac$ v simil>ly to ! pavilion girdle facets except t !y are %ort]4 ,! cr[n girdle facets %\ld be jo9$ 9 exactly ! same way z ! pavilion girdle facets4 ,:5 ^! facets are prop]ly cut1 ! cutt+ angle is aga9 *ang$1 ! arm rotat$1 & ! eight /> facets are cut4 ,?is completes ! cutt+ ( ! cr[n ( ! /one4 ,! cutt+ lap is remov$ f ! lap plate1 & ! poli%+ lap is secur$ into place4 ,! facets are c>efully poli%$ 9 ! same ord] t !y 7 cut4 ,aft] ! la/ /> facet has be5 poli%$1 ! /one is remov$ f ! dop-/ick4 ,any excess dop-wax is remov$ f ! /one by means ( a solv5t1 & ! full beauty ( ! f9i%$ gem is reveal$4 ,tumbl$ ,gems ,"o o!r me?od ( f9i%+ gem/ones t des]ves m5tion is tumbl+4 8,b>oque0 or 8free-=m0 /ones are produc$ 9 ?is mann]4 ,loose pebbles or pieces ( gem mat]ials left ov] f o!r cutt+ processes are plac$ 9 a small b>rel or specially con/ruct$ box ) loose c>borundum grit4 ,! b>rel is turn$ by means ( a small motor1 & ! abrasion ( ! pebbles & grit aga9/ ea* o!r t5ds to r\nd ! pebbles & give !m a f9ely pitt$ surface4 ,progressively f9] & f9] c>borundum grit is us$1 & ev5tually a poli%+ comp\nd4 ,! result is sev]al p\nds ( well-poli%$ gem pebbles ( v>i\s %apes & sizes4 ,^! b>oque /ones h f\nd rec5t favor 9 co/ume jewelry ( mod]n design4 ,! tumbl+ process is r sl[1 commonly requir+ sev]al days or weeks4 ,h[ev]1 little ef=t is involv$ on ! "p ( ! lapid>y1 &1 consequ5tly1 ! co/ ( mo/ tumbl$ or b>oque /ones is q mode/4 ,only gem mat]ial t is unsuitable = cutt+ 9 o!r mann]s %\ld be f9i%$ 9 ?is way4 ,illu/ration3 ,fig4 #ab4 ,prop] plac+ ( ! pavilion girdle facets4 ,left3 facets n jo9$4 ,c5t]3 facets ov]lapp$1 jo9$ too high4 ,"r3 correct plac+4 ,/one ,dop-wax ,dop-/ick ,*uck ,illu/ration3 ,fig4 #ac4 ,prop] sequ5ce ( cutt+ ( ! cr[n facets4 ,left to "r3 f\r ma9 facets2 all eight ma9 facets2 half ( ! cr[n girdle facets2 complet$ cr[n4 ,,texas ,,gem/ones ,amb] ,composition3 fossil res94 ,cry/al sy/em3 amorph\s4 ,h>dness3 ab\t #b4j to #b4e4 ,specific gravity3 v>iable1 f #a4je to #a4aj4 ,lu/]3 res9\s4 ,color3 br[n1 yell[1 r$1 orange1 & :ite4 ,/reak3 :ite to yell[i% to gray4 ,cleavage3 none4 ,fracture3 con*oidal4 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to transluc5t4 ,refractive index3 v>iable1 ab\t #a4ed4 ,burns ) a sweet1 p9ey odor4 ,ri* br[n to yell[i% amb] has be5 f\nd ne> ,eagle ,pass1 ,mav]ick ,c\nty1 9 ,cretace\s coal & on ,t]l+ua ,creek1 ,brew/] ,c\nty4 ,al?\gh mu* ( ?is mat]ial is transluc5t & ! quality suitable = lapid>y purposes1 ! pieces are seldom m ?an a fraction ( an in* 9 diamet]4 ,occasional f9ds ( poor quality br[ni% amb] h be5 report$ f ! ,t]ti>y =mations ( ! ,gulf ,coa/al ,pla91 b ?us f> no gem quality mat]ial has be5 f\nd4 ,! s(tness ( amb] limits its use to broo*es1 necklaces1 & o!r jewelry t is relatively safe f abrasion4 ,augite ,composition3 ,ca,mg,si,o2 may also conta9 iron1 alum9um1 & sometimes titanium4 ,cry/al sy/em3 monocl9ic4 ,h>dness3 #e to #f4 ,specific gravity3 #c4b to #c4f4 ,lu/]3 vitre\s to dull4 ,color3 d>k gre5i% br[n & gre5i% black4 ,/reak3 light grayi% gre54 ,cleavage3 two directions1 poor4 ,fracture3 con*oidal to unev54 ,t5acity3 brittle4 ,diaphaneity3 opaque to transluc5t4 ,refractive index3 v>iable1 ab\t #a4fj to #a4ga4 ,augite ( gem quality occurs ne> ,eagle ,flat1 ,hudspe? ,c\nty1 ,texas4 ,al?\gh ?is mat]ial is v d>k gre5i% br[n & n commonly ?\ght ( z a gem/one1 lapid>ies h us$ x to fa%ion black facet$ /ones & cabo*ons t resemble obsidian4 ,mo/ ( ! augite occurs z loose pieces & cry/al fragm5ts t h wea!r$ out ( ne>by igne\s rocks2 ! augite c also be f\nd 9 situ 9 ! igne\s rocks4 ,specim5s & pieces ( cutt+ quality #a in* 9 diamet] are common1 & fragm5ts ov] #b in*es 9 diamet] h be5 f\nd4 ,! augite is associat$ ) black sp9el & "s d>k gray to black pieces ( natural glass4 ,al?\gh ! facet$ & cabo*on-cut /ones are n p>ticul>ly attractive1 "s ( ! l>g] pieces ( augite might be utiliz$ = c>v+4 ,b]yl ,composition3 ,be,al7,si,o74 ,cry/al sy/em3 hexagonal4 ,h>dness3 #g4e to #h4j4 ,specific gravity3 #b4fc to #b4hj4 ,lu/]3 vitre\s4 ,color3 pale blue1 blue1 gre51 yell[1 br[ni%1 p9k1 & colorless4 ,/reak3 :ite4 ,cleavage3 "o direction1 v imp]fect4 ,fracture3 con*oidal to unev54 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to subtransluc5t4 ,refractive index3 #a4ef to #a4fj4 ,disp]sion3 l[4 ,gem-quality b]yl has n be5 report$ 9 ,texas4 ,a discussion ( b]yl is includ$ h]e9 because ! writ] believes x likely t b]yl ( gem quality w be f\nd 9 ,texas z a result ( future inve/igations & exploration4 ,b]yl cry/als h be5 f\nd 9 pegmatite dikes 9 ,llano1 ,blanco1 & ,gillespie c\nties4 ,^! cry/als are commonly sev]al in*es long & exce$ #a in* 9 diamet] b are v badly fractur$4 ,mo/ ( ! b]yl cry/als d n approa* gem quality & are entirely unsuitable = any lapid>y use4 ,! color ( ! cry/als f\nd ?us f> is blui%1 gre5i%1 p9ki% br[n1 yell[i%1 & colorless4 ,"s v t9y colorless b]yl cry/als h be5 f\nd t are transp>5t1 b ?us f> su* cry/als h be5 too small to be cut into gems4 ,f9e blue b]yl cry/als h be5 f\nd 9 ! ,frankl9 ,m\nta9s ne> ,el ,paso1 ,texas4 ,un=tunately1 ^! cry/als are s badly flaw$ & fractur$ t !y are n suitable = lapid>y use4 ,x seems likely t c>eful prospect+ ( ,texas pegmatites w reveal at lea/ "s gem-quality b]yl4 ,cele/ite ,composition3 ,sr,s,o4 ,cry/al sy/em3 or?orhombic4 ,h>dness3 #c4j to #c4e4 ,specific gravity3 #c4ie to #c4ih4 ,lu/]3 vitre\s4 ,color3 :ite1 blue1 gre5i%1 r$di%1 & br[ni%4 ,/reak3 :ite4 ,cleavage3 ?ree directions1 al?\gh "o ( ^! directions is n easily develop$4 ,fracture3 unev54 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to subtransluc5t4 ,refractive index3 #a4fb to #a4fc4 ,disp]sion3 mod]ate4 ,cele/ite is v seldom cut into gems4 ,be+ v s(t1 brittle1 & hav+ ?ree cleavages1 cele/ite is completely unsuitable = jewelry4 ,^! same prop]ties make ?is m9]al exce$+ly difficult to facet2 h[ev]1 facet$ /ones are se5 9 l>ge collections4 ,illu/ration3 ,fig4 #ad4 ,common cry/al =m ( ,travis ,c\nty cele/ite4 ,same cry/al =m z %[n 9 ,plate ,i1 ,a4 ,f9e cry/als ( colorless & blue gem-quality cele/ite 7,pl4 ,i1 ,a1 & fig4 #ad7 h be5 f\nd at ,m\nt ,bonnell & o!r localities we/ ( ,au/91 ,travis ,c\nty4 ,! cele/ite cry/als occur 9 vugs or geodes 9 lime/one4 ,! cry/als are mo/ly :ite or colorless & fractur$ ne> ! base or :]e atta*$1 b ! tips ( ! cry/als are commonly cle> cele/9e blue & completely free ( flaws4 ,cry/als sev]al in*es 9 l5g? h be5 f\nd1 b ! av]age size is ab\t #a in*4 ,! small] cry/als are frequ5tly m transp>5t & consequ5tly bett] suit$ = cutt+4 ,x is v difficult to obta9 cry/als t w all[ ! cutt+ ( flawless /ones ( m ?an #d or #e c>ats4 ,blui% & colorless cele/ite ( gem quality & f9e cry/als h be5 f\nd ne> ,lampasas1 ,lampasas ,c\nty1 & ne> ,br[nwood1 ,br[n ,c\nty1 b nei!r ( ^! localities has be5 v productive ( good gem mat]ial4 ,cele/ite geodes h be5 f\nd 9 p>ts ( ,coke1 ,fi%]1 & ,nolan c\nties1 b ^! geodes conta9 little gem mat]ial4 ,diamond ,composition3 c>bon4 ,cry/al sy/em3 isometric4 ,h>dness3 #aj4 ,specific gravity3 #c4ea to #c4ec4 ,lu/]3 adamant9e to greasy4 ,color3 br[n1 colorless1 p9k1 blue1 yell[1 & v>i\s o!r light colors2 r>ely deeply color$2 sometimes black4 ,cleavage3 f\r directions1 octah$ral1 p]fect4 ,fracture3 con*oidal4 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to opaque4 ,refractive index3 #b4db4 ,disp]sion3 high4 ,!re is only "o well-au!nticat$ f9d ( diamond 9 ,texas4 ,a small br[ni% diamond 0 f\nd 9 #aiaa on section #fd1 block #dd1 ,fo>d ,c\nty 7,/]rett1 #aiab1 pp4 #ajdj-ajda74 ,! exact weight ( ! /one has n be5 record$1 b "o au?ority e/imat$ t x 0 ( suffici5t size & cl>ity to yield a cut /one ( ab\t "o-qu>t] c>at4 ,! only diamond-be>+ rocks kn[n 9 ! ,unit$ ,/ates are 9 ,pike ,c\nty1 ,arkansas4 ,al?\gh _m o!r diamonds h be5 f\nd 9 ! ,unit$ ,/ates1 all 7 loose 9 gravels or /reams except = "s /ones at ! ,arkansas locality4 ,! fact t "o diamond 0 f\nd 9 ,fo>d ,c\nty does n mean t ! prospects ( f9d+ m diamonds 9 ,texas are mu* bett] !re ?an any:]e else 9 ! ,/ate4 ,x is highly unlikely t m ?an a v few diamonds w ev] be f\nd 9 ,texas1 & any /ones t may be f\nd 9 ! future are likely to be widely scatt]$4 ,epidote ,composition3 ,h,ca7,al1 ,fe7,si,o4 ,cry/al sy/em3 monocl9ic4 ,h>dness3 #f to #g4 ,specific gravity3 #c4be to #c4e4 ,lu/]3 vitre\s4 ,color3 yell[i% gre5 to br[ni% gre5 & br[n4 ,/reak3 uncolor$ to grayi%4 ,cleavage3 two directions4 ,fracture3 unev54 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to opaque4 ,refractive index3 ab\t #a4gb to #a4gg4 ,llano ,c\nty has furni%$ "s gre5 & br[ni%-gre5 epidote t is suitable = cutt+ into cabo*ons4 ,mo/ ( ! mat]ial t approa*es gem quality has come f contact metamorphic zones & is associat$ ) g>net1 qu>tz1 & "s s*eelite4 ,"s small cavities 9 ! rocks conta9 t9y transp>5t cry/als ( gem quality1 b ! l>ge/ obta9able flawless facet$ /ones w\ld probably be less ?an #ae po9ts4 ,facet$ /ones ( epidote are sometimes kn[n z pi/acite ow+ to _! common pi/a*io-gre5 color4 ,fluorite ,composition3 ,ca,f4 ,cry/al sy/em3 isometric4 ,h>dness3 #d4 ,specific gravity3 #c4j to #c4be4 ,lu/]3 vitre\s4 ,color3 violet1 blue1 colorless1 gre51 yell[1 br[n1 rose1 & crimson r$4 ,/reak3 :ite4 ,cleavage3 f\r directions1 octah$ral1 p]fect4 ,fracture3 subcon*oidal to spl9t]y4 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to subtransluc5t4 ,refractive index3 #a4dcd4 ,v f9e gre51 transp>5t fluorite has be5 f\nd ne> ,voca1 ,mason ,c\nty4 ,! fluorite occurs z vug fill+s 9 pegmatites1 associat$ ) cry/als ( p9k microcl9e & colorless qu>tz4 ,mo/ ( ! vugs h be5 completely fill$ by ! fluorite2 !re=e1 cry/als 7fig4 #ae7 ( ! fluorite are n too common4 ,masses ( fluorite sev]al p\nds 9 weight1 ri* gre51 & q transp>5t h be5 f\nd ne> ,voca4 ,transp>5t pieces an in* or m 9 diamet] are common4 ,illu/ration3 ,fig4 #ae4 ,common cry/al =m ( fluorite4 ,fluorite is mu* too s(t = ev]yday use 9 jewelry & because ( ! l[ refractive index does n yield brilliant facet$ /ones4 ,! p]fect f\r-directional cleavage1 relative s(tness1 & brittle t5acity ( ! m9]al make x difficult to facet4 ,facet$ /ones are seldom se5 outside ( collections4 ,cabo*ons are also difficult to cut f ?is mat]ial1 b ! ri* color obta9$ is ample rew>d = ! "t & c>e necess>y 9 cutt+4 ,fluorite occurs at sev]al o!r localities 9 ,texas1 notably 9 ,hudspe?1 ,brew/]1 ,presidio1 ,llano1 & ,burnet c\nties1 b n commonly 9 gem quality or colors t w>rant its use z gem mat]ial4 ,fossil ,wood ,wood t is buri$ 9 silica-ri* s$im5ts is commonly replac$ by qu>tz1 agate1 or opal4 ,! wood /ructure1 includ+ a l>ge numb] ( ! annul> r+s1 knots1 small bran*es1 & b>k1 may be pres]v$4 ,?is process ( replacem5t by silica is believ$ to take consid]able "t4 ,pres]vations by o!r means 7see ,jet1 p4 #bb7 are kn[n1 b silica replacem5ts are mo/ commonly us$ z gem mat]ials4 ,fossil wood is (t5 us$ by lapid>ies z gem mat]ial :5 m9]al replacem5t pres]ves ! wood /ructure suffici5tly well & :5 v>i\s impurities color ! replacem5t mat]ial attractively4 ,excell5t gem-quality fossil wood 7,pl4 ,i1 ,b7 has be5 f\nd at a great numb] ( localities 9 ,texas4 ,agatiz$ & opaliz$ wood occurs 9 great abundance along ! outcrops ( ,eoc5e & ,oligoc5e /rata ( ! ,texas ,gulf ,coa/al ,pla94 ,mu* ( ?is mat]ial is v well suit$ = cabo*ons1 book5ds1 & o!r lapid>y uses4 ,! pres]vation is especially good at num]\s localities 9 ,wa%+ton1 ,lee1 ,fayette1 & ,gonzales c\nties1 & ! v>iety ( colors1 su* z blui%1 gray1 br[n1 r$1 yell[1 & black1 makes ?is mat]ial especially s\ght aft] by 8rock-h\nds40 ,"s ( ! agatiz$ & opaliz$ wood fluoresces yell[ or gre5 "u ultra-violet light4 ,! fossil wood is sometimes f\nd z /umps1 limb sections1 or l>ge trunk fragm5ts1 b ! great majority ( ! gem mat]ial is f\nd z small brok5 fragm5ts or /ream-roll$ cobbles4 ,fossil palm wood is by f> ! mo/ s\ght aft] v>iety because ?is mat]ial displays 8eyes0 & tube-l /ructures t yield v attractive cabo*ons & cab9et specim5s4 ,texas fossil palm wood is highly reg>d$ by cutt]s f all p>ts ( ! c\ntry1 & ?is mat]ial is ?\ght by _m lapid>ies to be "s ( ! f9e/ gem-quality fossil wood 9 ! ,unit$ ,/ates4 ,gravel pits & riv] gravels 9 ,live ,oak ,c\nty h produc$ v f9e agatiz$ wood4 ,al?\gh ! gem mat]ial does n seem to be z abundant 9 ?is area z x is 9 c\nties to ! nor!a/1 ! vivid colors & excell5t pres]vation ( ! fossil wood 9 ,live ,oak ,c\nty h attract$ collectors f all ov] ! ,/ate4 ,! fossil wood usually occurs z l>ge r\nd$ cobbles 9 ! /reams4 ,mu* ( ?is mat]ial is q transluc5t :5 cut & conta9s v>i\s %ades ( br[n1 orange1 & r$4 ,! gravels ( ! ,rio ,gr&e h produc$ "s fossil wood 9 addition to ! excell5t agate t is also f\nd !re4 ,mo/ ( ! fossil wood f\nd 9 ^! gravels is v well pres]v$1 b ! colors are commonly dull %ades ( br[n4 ,occasional f9e r$ & yell[ specim5s h be5 recov]$ f ! ,rio ,gr&e gravels1 b ^! are r>e4 ,good agatiz$ wood has be5 f\nd 9 & ne> ,palo ,duro ,canyon1 ,arm/rong ,c\nty1 ab\t #ej miles s\!a/ ( ,am>illo4 ,l>ge trunk sections are n uncommon1 b mo/ ( ! mat]ial ( cutt+ quality is obta9$ f small fragm5ts4 ,! ,palo ,duro ,canyon fossil wood greatly resembles ! fam\s ,arizona ,petrifi$ ,=e/ wood b is n ne>ly z pl5tiful4 ,! ,palo ,duro wood conta9s yell[1 br[n1 r$1 & blui% colors mo/ commonly4 ,"s ( ! wood-produc+ area is )9 ,palo ,duro ,canyon ,/ate ,p>k :i* is1 ( c\rse1 clos$ to collect+4 ,! surr\nd+ area has be5 work$ dilig5tly by local collectors1 b new pieces ( wood are expos$ aft] heavy ra9s4 ,webb & ,duval c\nties h also produc$ "s good fossil wood specim5s4 ,gadol9ite ,composition3 ,be,fe,y,si,o4 7,v>i\s o!r r>e-e>? elem5ts may sub/itute into ?is m9]al /ructure47 ,cry/al sy/em3 monocl9ic4 ,h>dness3 #f4e to #g4j4 ,specific gravity3 ab\t #d4b4 ,lu/]3 vitre\s to greasy4 ,color3 black2 9 ?9 spl9t]s d>k bottle gre54 ,/reak3 :ite to gre5i%4 ,cleavage3 none4 ,fracture3 con*oidal to spl9t]y4 ,t5acity3 brittle4 ,diaphaneity3 opaque to subtransp>5t 9 ?9 pieces4 ,refractive index3 v>iable1 ab\t #a4gg to #a4hb4 ,gadol9ite z a cut gem is n se5 outside ( l>ge collections2 h[ev]1 x c be facet$ into black opaque /ones ( little beauty b ( great int]e/ to collectors4 ,! be/ kn[n locality ( ?is m9]al 9 ! ,unit$ ,/ates is ,b>+] ,hill1 ,llano ,c\nty1 ,texas4 ,un=tunately1 ?is locality 0 completely flood$ by ! completion ( ,bu*anan ,dam 9 #aich4 ,masses & r\gh cry/als ( gadol9ite weigh+ ov] #ajj p\nds 7 m9$ f ?is locality4 ,! gadol9ite occurr$ 9 a l>ge1 v co>se-gra9$ pegmatite dike associat$ ) qu>tz1 microcl9e1 & fluorite1 z well z allanite1 f]gusonite1 niv5ite1 cyrtolite1 ?orogummite1 & v>i\s o!r r>e m9]als4 ,"s ( ! m9]als 9 ! dike occurr$ 9 v l>ge masses4 ,"o qu>tz mass ov] #dj feet 9 diamet] 0 not$1 & microcl9e masses up to #cj feet 9 diamet] 7 n uncommon4 ,mu* ( ! gadol9ite 0 us$ by indu/rial firms z a s\rce ( ?orium comp\nds1 al?\gh "s specim5 & gem mat]ial f\nd its way into museums & private collections4 ,because ! locality 0 work$ mo/ly f #aiaj to ab\t #aibe & because s9ce #aich ! wat]s ( ,lake ,bu*anan h completely flood$ ! entire area1 mat]ial f ?is locality is n[ exce$+ly difficult to obta94 ,! collection ( ! ,smi?sonian ,in/itution1 ,wa%+ton1 ,d4,c41 conta9s a cut & poli%$ gem ( ,b>+] ,hill gadol9ite t weighs #h4f c>ats4 ,?is m9]al is radioactive because ( ! pres5ce ( uranium1 ?orium1 & o!r r>e radioactive elem5ts4 ,g>net ,! g>net gr\p ( m9]als is v>iable 9 composition4 ,li/$ bel[ are ! pure memb]s ( ?is gr\p1 b g>nets f\nd 9 nature are usually a mixture ( two or m ( ^! end memb]s4 ,alum9um g>net-- ,grossul>ite 7calcium-alum9um g>net71 ,ca,al7,si,o7 ,pyrope 7magnesium-alum9um g>net71 ,mg,al7,si,o7 ,alm&ite 7iron-alum9um g>net71 ,fe,al7,si,o7 ,spess>tite 7manganese-alum9um g>net71 ,mn,al7,si,o7 ,iron g>net-- ,&radite 7calcium-iron g>net71 ,ca,fe7,si,o72 may conta9 magnesium1 titanium1 & yttrium ,*romium g>net-- ,uv>ovite 7calcium-*romium g>net71 ,ca,cr7,si,o7 ,s9ce alm&ite is ! only v>iety ( g>net kn[n to occur commonly 9 gem quality 9 ,texas1 ! foll[+ prop]ties are = alm&ite except :]e not$4 ,cry/al sy/em3 isometric 7all v>ieties74 ,h>dness3 ab\t #g4e4 ,specific gravity3 #d4be4 ,lu/]3 vitre\s to res9\s4 ,color3 r$1 deep r$1 & br[ni% r$ 7o!r v>ieties also yell[1 :ite1 orange1 p9k1 black1 & gre574 ,/reak3 :ite4 ,cleavage3 none4 ,fracture3 subcon*oidal to unev54 ,t5acity3 brittle to t\gh4 ,diaphaneity3 transp>5t to subtransluc5t4 ,refractive index3 ab\t #a4hc4 ,good cry/als ( gem-quality alm&ite g>net h be5 f\nd 9 ,llano1 ,blanco1 ,burnet1 & ,gillespie c\nties4 ,9 s\!a/ ,llano ,c\nty1 nor?we/ ,blanco ,c\nty1 & nor!a/ ,gillespie ,c\nty1 ! /ones mo/ly occur 9 /ream gravels :]e !y h collect$ aft] be+ wea!r$ out ( compact mica s*i/s4 ,ow+ to ! fact t mo/ ( ! g>nets h n be5 transport$ v f> f _! s\rce1 ! /ones commonly %[ good cry/al =m 7,pl4 ,,ii1 ,a74 ,all ( ! g>nets f "o locality commonly d n h exactly ! same cry/al =m4 ,! g>nets are mo/ly widely scatt]$ 9 ! /ream gravels b c be f\nd conc5trat$ beh9d rocks & on small gravel b>s4 ,_m ( ! cry/als are less ?an "o-eigh? in* 9 diamet]2 h[ev]1 good cry/als "o-f\r? to "o-half in* 9 diamet] are common4 ,mo/ ( ! /ones are too fractur$ or h too _m inclusions to yield gems1 b _m transp>5t /ones h be5 f\nd4 ,! transp>5t cry/als usually yield flawless deep r$ facet$ /ones ( #b c>ats or less4 ,"s ( ! /ones t conta9 too _m inclusions to facet are cut z cabo*ons & are !n (t5 kn[n z c>buncle4 ,small g>net fragm5ts h be5 f\nd 9 /reams & 9 gneisses & pegmatites ne> ,ca/ell1 ,llano ,c\nty1 b !y are n commonly ( gem quality4 ,occasional small gem-quality g>nets h be5 f\nd 9 pegmatites & contact metamorphic zones 9 ,burnet ,c\nty4 ,g>nets h also be5 f\nd 9 sev]al o!r c\nties1 notably ,mason1 ,el ,paso1 ,hudspe?1 & ,culb]son1 b no /ones ( facet quality h be5 report$4 ,jet ,composition3 a v>iety ( br[n coal or lignite4 ,/ructure3 woody4 ,h>dness3 #c to #d4 ,specific gravity3 ab\t #a4cj to #a4ce4 ,lu/]3 dull4 ,color3 black1 br[ni% black4 ,/reak3 br[n to br[ni% black4 ,cleavage3 none4 ,fracture3 unev5 to smoo?4 ,t5acity3 t\gh to slightly brittle4 ,diaphaneity3 opaque4 ,burns ) a sooty yell[i% flame4 ,jet is a type ( fossil wood 9 :i* !re has be5 suffici5t *emical *ange to make ! wood relatively h>d & black )\t de/roy+ ! woody /ructure4 ,! be/ specim5s ( jet poli% into lu/r\s black cabo*ons4 ,jet occurs 9 ,presidio ,c\nty z compress$ & flatt5$ trunks ( trees 9 a ?9 lay] ( coal & lignite 9 ,cretace\s /rata #ajj to #bjj feet /ratigraphically bel[ ! ,san ,c>los b$s4 ,specim5s ( 8jet0 h be5 f\nd 9 "s ( ! lignitic ,t]ti>y /rata ( ! ,texas ,gulf ,coa/al ,pla92 h[ev]1 ?is mat]ial is mo/ly s(t1 br[ni%1 & n ( gem quality4 ,labradorite ,composition3 ,na,al,si,o1 #ej to #cj2 ,ca,al,si,o1 #ej to #gj4 ,cry/al sy/em3 tricl9ic4 ,h>dness3 #f4j to #f4e4 ,specific gravity3 ab\t #b4fj4 ,lu/]3 vitre\s to sometimes pe>ly4 ,color3 /raw yell[1 :ite1 gre5i%1 gray1 r$di%1 blui%1 & gre54 ,sometimes %[s a play ( colors on p>ticul> cleavage surfaces4 ,/reak3 uncolor$4 ,cleavage3 ?ree directions4 ,fracture3 unev5 to con*oidal4 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to transluc5t4 ,refractive index3 ab\t #a4ef4 ,disp]sion3 l[4 ,v f9e facet-quality labradorite has be5 f\nd ab\t #bj miles s\? ( ,alp9e1 ,brew/] ,c\nty4 ,! labradorite occurs loose 9 ! soil z slightly wea!r$ or fro/$ cleavage fragm5ts1 commonly %[+ "o or m cry/al faces 7,pl4 ,,ii1 ,b74 ,! pale-yell[ or /raw-yell[ color ( ^! fragm5ts1 z well z _! lack ( int]nal imp]fections1 makes ^! /ones excell5t gem mat]ial4 ,individual pieces t exce$ ?ree-f\r?s in* 9 _! longe/ dim5sions are r>e4 ,cut /ones ( m ?an #e or #f c>ats f ?is locality are sc>ce4 ,! s\rce ( ?is mat]ial is unc]ta91 b x is probably wea!r+ out ( an und]ly+ igne\s rock4 ,microcl9e ,composition3 ,k,al,si,o4 ,cry/al sy/em3 tricl9ic4 ,h>dness3 #f4j to #f4e4 ,specific gravity3 #b4ed to #b4eg4 ,lu/]3 vitre\s to pe>ly4 ,color3 :ite1 pale yell[1 r$1 blue gre51 blui%4 ,/reak3 :ite4 ,cleavage3 f\r directions1 usually ?ree ( ^! di/9ct4 ,fracture3 unev54 ,t5acity3 brittle ,diaphaneity3 transp>5t to transluc5t4 ,refractive index3 ab\t #a4eb to #a4ec4 ,v f9e cry/als ( blue microcl9e h be5 f\nd ea/ ( ,packsaddle ,m\nta9 & ne> ,k+sl& 9 ,llano ,c\nty4 ,cry/als exce$+ #a foot 9 l5g? h be5 f\nd1 al?\gh mo/ are only a few in*es long4 ,! color ( ! microcl9e is mo/ly pale blue1 b "s cry/als are d>k]4 ,microcl9e cry/als associat$ ) milky or ve9 qu>tz1 smoky qu>tz1 "s biotite1 & r>ely cassit]ite occur 9 pegmatite dikes :i* v>y 9 size f a few in*es to sev]al feet 9 ?ickness4 ,! color ( ?is microcl9e is pale 9 comp>ison to microcl9e f "s o!r localities 9 ! ,unit$ ,/ates1 b ! ,texas blue microcl9e does yield pleas+ cabo*ons4 ,p]fect cry/als ( ?is mat]ial are priz$ by collectors4 ,blue or gre5i% microcl9e is (t5 call$ amazonite or amazon /one4 ,blui% microcl9e associat$ ) qu>tz & topaz has also be5 report$ ne> ,katemcy1 ,mason ,c\nty4 ,r$ microcl9e is common 9 sev]al c5tral ,texas c\nties & is a prim>y con/itu5t ( _m ( ! igne\s rocks 9 ^? c\nties4 ,l>ge cry/als ( p]?itic r$ microcl9e occur 9 pegmatite dikes ( ,mason1 ,llano1 ,burnet1 & ,gillespie c\nties4 ,any feldsp> qu>ry or o!r pegmatite m9+ op]ation 9 any ( ^! c\nties is likely to conta9 l>ge r$ microcl9e cry/als & fragm5ts4 ,un=tunately1 ! good cry/als t may h be5 pres5t are (t5 %att]$ by bla/+ dur+ qu>ry+ op]ations4 ,feldsp> qu>ries 9 nor!a/]n ,gillespie ,c\nty h yield$ "s good r$ cabo*on mat]ial z well z good cry/als4 ,"h ! microcl9e occurs ) milky & smoky ve9 qu>tz1 smoky qu>tz cry/als1 cle> qu>tz cry/als1 gre5i% muscovite1 & biotite4 ,_m ( ! old] qu>ries 9 ,gillespie ,c\nty h n be5 active = "s "t1 & ! dumps & qu>ry walls h be5 dilig5tly se>*$ by collectors4 ,illu/ration3 ,fig4 #af4 ,cry/al faces on microcl9e specim5 %[n 9 ,plate ,,iii1 ,a4 ,_m ( ! pegmatite dikes ne> ,lake ,bu*anan 9 ,llano & ,burnet c\nties h produc$ "s good r$ microcl9e specim5s & cutt+ mat]ial 7,pl4 ,,iii1 ,a1 & fig4 #af74 ,_m ( ^! cry/als are m p9ki% ?an ^? 9 ,gillespie ,c\nty1 b ?is is commonly due to ! fact t ! cry/al faces ( ! ,lake ,bu*anan area cry/als are some:at m wea!r$ ?an ! fre% ,gillespie ,c\nty cry/als4 ,num]\s o!r local areas 9 ! c\nties m5tion$1 z well z "s localities 9 ,hudspe? & ,culb]son c\nties1 h also produc$ small am\nts ( r$ & p9k microcl9e ( gem quality4 ,obsidian ,composition3 volcanic glass4 ,/ructure3 amorph\s4 ,h>dness3 #e4j to #e4e4 ,specific gravity3 #b4c to #b4e4 ,lu/]3 vitre\s4 ,color3 black1 d>k gray1 r$di%1 br[n1 blui%1 & gre5i%4 ,/reak3 :ite4 ,cleavage3 none4 ,fracture3 con*oidal4 ,t5acity3 brittle4 ,diaphaneity3 transluc5t to ne>ly opaque4 ,refractive index3 v>iable1 ab\t #a4de to #a4ec4 ,gem-quality black & d>k-gray obsidian has be5 f\nd 9 ,presidio ,c\nty associat$ ) extrusive igne\s rocks4 ,! obsidian 9 ?is area is too opaque to s]ve z attractive facet$ /ones b is f\nd 9 pieces ( suffici5t size & quality to yield nice cabo*ons4 ,"s ( ! small wea!r$ pieces ( ?is mat]ial resemble tektite 9 outw>d appe>ance2 9 fact1 ! 8valv]dites0 mi/ak5 orig9ally = tektites are pebbles ( wea!r$ obsidian 9 t]race gravel ( ,val ,v]de ,c\nty4 ,obsidian takes a high poli% b is v s5sitive to heat4 ,/ones t are slightly ov]heat$ dur+ gr9d+ or s&+ w quickly %att]4 ,obsidian ( gem quality has be5 report$ also 9 ,brew/] ,c\nty4 ,opal ,composition3 ,si,on,h,o4 ,/ructure3 amorph\s4 ,h>dness3 #e4e to #f4e4 ,specific gravity3 #a4i to #b4c4 ,lu/]3 subvitre\s to pe>ly4 ,color3 :ite1 blui%1 p9k1 br[n1 yell[1 & gray4 ,/reak3 :ite4 ,cleavage3 none4 ,fracture3 con*oidal4 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to ne>ly opaque4 ,refractive index3 #a4dc4 ,opal o!r ?an z fossil or opaliz$ wood 7pp4 #bj-ba7 occurs at ! foll[+ sev]al localities 9 ,texas4 ,approximately #af miles s\? ( ,alp9e1 ,brew/] ,c\nty1 preci\s opal occurs 9 v small seams & z cavity fill+s 9 v h>d p9ki%-br[n rhyolite4 ,?is opal is milky or blui% & commonly exhibits small fla%es ( blue1 gre51 r$1 & orange fire4 ,individual pieces ( ?is opal are mo/ly q small1 r>ely ov] "o-f\r? in* 9 diamet]1 & v difficult to remove f ! t\gh rhyolite matrix4 ,local lapid>ies h cut int]e/+ cabo*ons f ?is mat]ial 9 :i* sev]al small pat*es ( opal t are close toge!r 9 ! matrix are includ$ 9 ! same cabo*on4 ,small f9ds ( opal associat$ ) rhyolites & basalts h come f o!r localities 9 we/ ,texas1 b ! opal mo/ly does n display en\gh play ( colors to w>rant its use z gem mat]ial4 ,ne> ,fre]1 ,duval ,c\nty1 "s v attractive common opal has be5 f\nd4 ,! opal is color$ v>i\s %ades ( p9k1 blue1 & yell[ & 9 c]ta9 local areas occurs z fragm5ts t are cem5t$ toge!r by cle> *alc$ony4 ,v>i\s colors are commonly f\nd 9 ! same piece1 & su* mat]ial yields h&some cabo*ons4 ,al?\gh ! area has nev] be5 work$ comm]cially1 x has be5 hunt$ by collectors & cutt]s = sev]al ye>s4 ,pe>l ,pe>ls are ! result ( ! secretion ( calcium c>bonate by v>i\s %ellfi% ar\nd s& gra9s1 p>asitic organisms1 %ell fragm5ts1 or o!r =eign objects t h 9 "s way ent]$ ! body cavity ( ! %ellfi%4 ,s9ce ! %ellfi% is unable to expel ^! irritat+ p>ticles or organisms1 x deposits successive lay]s ( calcium c>bonate ar\nd ! =eign sub/ance to make x smoo!r & less irritat+4 ,al?\gh pe>ls are pr9cipally calcium c>bonate1 !y also conta9 small am\nts ( an organic sub/ance1 call$ con*iol91 & wat]4 ,pe>ls are f\nd 9 %ellfi% t live 9 ei!r fre% or salt wat]4 ,few pe>ls are sph]ical 9 %ape2 mo/ are r\nd$ b some:at irregul> & are kn[n z b>oque pe>ls4 ,good quality pe>ls are ! only gem/one commonly sold by ! gra91 a unit ( weight equal to #j4be c>at or #j4je gram4 ,! pe>l gra9 is n ! same unit ( weight z ! ,troy gra94 ,9 ,texas1 pe>ls h be5 f\nd 9 fre%-wat] clams 9 mo/ ( ! major riv]s & /reams1 notably 9 ! ,brazos1 ,con*o1 ,colorado1 ,guadalupe1 ,llano1 ,nueces1 ,sab9e1 ,rio ,gr&e1 & ,tr9ity ,riv]s4 ,sev]al ,texas lakes h also yield$ pe>ls1 notably ,caddo ,lake & o!r lakes 9 nor?-c5tral & nor!a/ ,texas4 ,small pe>ls are frequ5tly f\nd along ! ,texas ,gulf ,coa/ 9 edible oy/]s & o!r common %ellfi%4 ,fossil pe>ls h also be5 f\nd b because ( _! d>k5$ appe>ance are ( value only z curiosities4 ,! pe>ls ?us f> f\nd 9 ,texas h be5 ( relatively poor quality & %[ little or no iridesc5ce4 ,^! pe>ls h little value except z curiosities1 al?\gh "o writ] has /at$ t ! discov]y ( pe>ls 9 ! ,nueces ,riv] l$ to ! orig9al ,spani% settlem5t ( ! ,/ate 7,bak]1 #aice1 p4 #efi74 ,qu>tz ,composition3 ,si,o4 ,cry/al sy/em3 hexagonal4 ,h>dness3 #g4 ,specific gravity3 #b4fe to #b4ff 9 cry/als4 ,lu/]3 vitre\s1 also waxy1 greasy1 & dull4 ,color3 mo/ (t5 colorless1 br[n1 yell[1 violet2 sometimes gre51 r$1 blue1 & black2 cryptocry/all9e v>ieties (t5 v>i\sly color$ by impurities4 ,/reak3 :ite4 ,cleavage3 indi/9ct4 ,fracture3 con*oidal to spl9t]y4 ,t5acity3 brittle to t\gh4 ,diaphaneity3 transp>5t to opaque4 ,refractive index3 #a4edd to #a4eec4 ,! qu>tz family gem/ones c be divid$ into two gr\ps = purposes ( description4 ,! fir/ gr\p is ! cry/all9e v>ieties1 or ^? qu>tz v>ieties t commonly occur 9 di/9ct cry/als4 ,! second gr\p is ! cryptocry/all9e v>ieties1 or ^? qu>tz v>ieties t occur z irregul> masses t are compos$ ( _m microscopic cry/als4 ,! cry/all9e v>ieties are usually mu* m transp>5t & are mo/ (t5 se5 z facet$ /ones4 ,! cryptocry/all9e v>ieties v>y f subtransp>5t to opaque & are almo/ always cut z cabo*ons4 ,,cry/all9e ,,v>ieties ,ame?y/ 7violet to purple-color$ qu>tz74--,a nor!a/]n ,gillespie ,c\nty locality kn[n z ,ame?y/ ,hill has produc$ q a numb] ( f9e light to m$ium violet ame?y/ cry/als :i* occur 9 qu>tz ve9s & geodes associat$ ) s]p5t9e & talc4 ,_m cry/als h be5 f\nd loose 9 ! soil4 ,! ame?y/ t5ds to be v irregul>ly color$ 9 zones p>allel to ! cry/al faces4 ,9 _m1 ! base ( ! cry/al is colorless or :ite & only ! t]m9ation is violet4 ,cry/als up to #c in*es long h be5 f\nd at ?is locality1 b ! av]age size is mu* less4 ,! surface at ?is locality is almo/ entirely deplet$ ( ame?y/1 ) only an occasional small cry/al or fragm5t to be se54 ,h[ev]1 small excavations are /ill sometimes productive4 ,good gr\ps ( pale ame?y/ cry/als h be5 f\nd 9 qu>tz ve9s ne> ! old t[n site ( ,ox=d1 ,llano ,c\nty4 ,! occurr5ce seems to be mu* ! same z ! ,ame?y/ ,hill locality4 ,little exploration = gem/ones has be5 done 9 ?is area1 & future discov]ies seem likely4 ,*alc$ony geodes l9$ ) ame?y/ cry/als h be5 f\nd 9 ,brew/]1 ,presidio1 ,culb]son1 & ,hudspe? c\nties1 b ! occurr5ces are scatt]$4 ,! cry/als are seldom l>ge en\gh to yield gems ( m ?an #c c>ats & are mo/ly v light color$4 ,a few pieces ( gem-quality ame?y/ h be5 f\nd 9 ,burnet ,c\nty4 ,citr9e 7yell[ qu>tz74--,v little gem-quality citr9e has be5 report$ 9 ,texas4 ,"s small citr9e cry/als h be5 f\nd at ,ame?y/ ,hill 9 nor!a/]n ,gillespie ,c\nty1 b few are ( suffici5t size or color to yield good gems4 ,! writ] has se5 "o citr9e cry/al t 0 f\nd 9 ! gravels ( a small /ream 9 ea/]n ,llano ,c\nty ne> ,bu*anan ,dam4 ,! cry/al weighs ab\t #a ounce & is p]fectly cle>1 light gold5 yell[1 & flawless4 ,h[ev]1 a fur!r se>* ( ! /ream gravels fail$ to produce any o!r citr9es4 ,rock cry/al 7colorless qu>tz74--,num]\s localities 9 ,texas produce ?is colorless v>iety ( qu>tz1 :i* is ! mo/ common v>iety ( facet quality qu>tz & consequ5tly is ( little value4 ,rock cry/al occurs at _m localities 9 ,burnet1 ,llano1 & ,mason c\nties4 ,! cry/als mo/ly occur 9 pegmatite dikes or 9 /ream gravels :]e !y h be5 wea!r$ out ( _! p>5t rock4 ,"s f9e colorless qu>tz cry/als h be5 f\nd ne> ,voca1 ,mason ,c\nty1 9 wea!r$ pegmatite dikes & also loose 9 ! s&s ( ne>by /reams4 ,cry/als f ?is locality are (t5 /a9$ ) r$di% iron oxide on _! out] surfaces4 ,"s ( ! rock cry/al f\nd ne> ,katemcy1 ,mason ,c\nty1 %[s a/]ism :5 cut ) ! prop] ori5tation4 ,f9e cle> colorless cry/als up to #h in*es long h be5 f\nd 9 ! pegmatite dikes ne> ,lake ,bu*anan 9 bo? ,llano & ,burnet c\nties4 ,sev]al localities ne> ,en*ant$ ,rock 9 ,llano ,c\nty h also produc$ "s good colorless cry/als4 ,feldsp> qu>ries 9 l>ge pegmatites 9 nor!a/]n ,gillespie ,c\nty h yield$ attractive qu>tz cry/als1 "s ( :i* conta9 smoky phantom cry/als & t\rmal9e inclusions4 ,"s pieces ( rock cry/al enclos+ gre51 ne$le-l act9olite cry/als h be5 f\nd ne> ! ,llano-,gillespie-,blanco ,c\nty corn]4 ,?is mat]ial is n suitable = facet$ gems b does l5d itself to int]e/+ & attractive cabo*ons4 ,colorless qu>tz cry/als commonly are f\nd l9+ small *alc$ony geodes 9 ,brew/]1 ,presidio1 ,culb]son1 ,hudspe?1 ,reeves1 & ,jeff ,davis c\nties4 ,^! cry/als are mo/ commonly less ?an #a in* long b are mo/ly v cle>4 ,rock cry/al has be5 f\nd 9 crevices ( petrifi$ wood 9 _m ea/ & s\!a/ ,texas c\nties1 al?\gh ! cry/als are mo/ly q small4 ,_m less] occurr5ces ( rock cry/al1 too num]\s to m5tion1 are locat$ )9 ! ,/ate4 ,rose qu>tz 7p9k qu>tz74--,rose qu>tz occurs at v>i\s localities 9 ,burnet1 ,llano1 ,mason1 & ,gillespie c\nties1 b ! am\nt ( mat]ial is mo/ly small & ! great] "p unsuitable = gem purposes4 ,"s good p9k rose qu>tz occurs ne> ,t[n ,m\nta91 ,llano ,c\nty1 b ?is mat]ial does n h flawless areas l>ge en\gh to yield facet$ /ones ( m ?an a few c>ats4 ,rose qu>tz is always slightly milky1 or cl\dy1 & does n cut into brilliant facet$ /ones4 ,! ,t[n ,m\nta9 rose qu>tz has be5 cut into attractive cabo*ons4 ,smoky qu>tz 7br[n1 yell[-br[n1 & gold5-br[n qu>tz74--,sev]al ,texas localities h produc$ f9e smoky qu>tz4 ,b>+] ,hill1 a not$ r>e-e>? m9]als pegmatite locality 9 ,llano ,c\nty1 conta9$ "s smoky qu>tz cry/als t 7 e/imat$ to weigh ov] #a1jjj p\nds1 & ! locality produc$ _m small] cry/als t 7 ( gem quality4 ,b>+] ,hill 0 flood$ by ! completion ( ,bu*anan ,dam 9 #aich & is pres5tly "u ! wat]s ( ,lake ,bu*anan4 ,a few f9e gold5-br[n gem-quality cry/als h be5 f\nd along ! lake %ore & 9 small pegmatites ne>by 7,pl4 ,,iii1 ,b474 ,feldsp> qu>ries 9 nor!a/]n ,gillespie ,c\nty h produc$ smoky qu>tz cry/als t exce$ #a foot 9 l5g?1 b ^! cry/als are mo/ly flaw$1 possibly z a result ( bla/+1 & mo/ly conta9 only small cle> areas4 ,good color smoky qu>tz cry/als are f\nd ) topaz 9 ! pegmatites & /ream b$s 9 ,mason ,c\nty1 ne> ,/reet]1 ,grit1 & ,katemcy4 ,^! cry/als t5d to be light] color$ ?an ^? ne> ,lake ,bu*anan1 b !y commonly conta9 l>ge flawless areas4 ,,cryptocry/all9e ,,v>ieties ,*alc$ony4--,:5 free f impurities ( v>i\s oxides & o!r comp\nds1 *alc$ony has little to r5d] x pleas+ z a gem/one4 ,x is mo/ly gray1 :ite1 br[n1 or blui% & commonly has a waxy lu/]4 ,"s ( ! *alc$ony f\nd along ! ,rio ,gr&e ,valley & 9 we/ ,texas w take dyes1 & local lapid>ies h _h "s success 9 dye+ ?is mat]ial v>i\s %ades ( blue1 gre51 yell[1 & r$4 ,:5 ! *alc$ony is naturally color$ & v>iegat$1 usually 9 b&s1 mossy figures1 or d5dritic =ms1 x is call$ agate4 ,agate 7v>iegat$ *alc$ony74--,! wide v>iety ( m>k+s & colors available toge!r ) ! ease ( cutt+ make agate a favorite ( _m lapid>ies4 ,f9e agate has be5 f\nd at num]\s localities 9 we/ & s\? ,texas4 ,f9e plume agate1 fam\s ?r\gh\t ! ,unit$ ,/ates1 is f\nd s\? ( ,alp9e4 ,plume agate is *>act]iz$ by d5dritic or tree-l inclusions & is mo/ly cut into v h&some cabo*ons4 ,! agate f s\? ( ,alp9e commonly conta9s black1 r$1 yell[1 or br[n plumes )9 ! same piece4 ,! v>iety ( colors & lack ( porosity ( ?is agate make x highly desir$ among lapid>ies4 ,! agate occurs loose on ! surface ( ! gr\nd & 9 ! soil 9 small nodules t h a v r\gh1 br[ni% surface4 ,^! nodules are mo/ly less ?an #c in*es 9 diamet]1 al?\gh specim5s ( gem quality h be5 f\nd t exce$ #bjj p\nds4 ,"s v f9e agate has be5 f\nd 9 ! vic9ity ( ,ne$le ,peak1 ,presidio ,c\nty4 ,?is mat]ial is mo/ly gre5 moss agate 9 cle> *alc$ony & commonly conta9s small yell[ 8sun-bur/0 figures4 ,! contra/+ yell[ & gre5 design makes v beautiful cabo*ons4 ,f9e agate has be5 f\nd s\? ( ,m>fa1 ,presidio ,c\nty4 ,?is agate is mo/ly cle> *alc$ony ) black1 yell[1 or v>i\sly color$ plumes1 moss1 or 8b\quet-l0 figures4 ,num]\s o!r localities 9 ,presidio & ,brew/] c\nties h produc$ good agate4 ,v>i\s am\nts ( agate1 jasp]1 & *alc$ony occur 9 ! gravels ( ! ,rio ,gr&e 9 v>y+ quantities f ,big ,b5d ,national ,p>k d[n/ream to ,br[nsville4 ,?is agate is f\nd bo? 9 ! pres5t riv] gravels & 9 ! old] riv] gravels t n[ are locat$ on ne>by hills & slopes up to sev]al miles nor? or s\? ( ! pres5t ,rio ,gr&e4 ,! greate/ conc5tration ( agate & relat$ gem mat]ials seems to be 9 ! area betwe5 ,l>$o & ,rio ,gr&e ,city4 ,va/ quantities ( excell5t gem mat]ial h be5 remov$ f ?is area = _m ye>s 7,pl4 ,,iv74 ,! agate occurs z r\nd$1 /ream-worn cobbles & commonly has a ?9 :ite coat+ t makes x difficult to di/+ui% f ! abundant *]t & o!r rocks4 ,! agate occurs 9 cobbles t are mo/ly #c to #f in*es 9 diamet]1 b specim5s ( gem quality t exce$ twice ?is size are kn[n4 ,! agate v>ies greatly 9 design & color4 ,plume1 moss1 b&$1 & sag5itic agate occur 9 ^! gravels 9 a wide v>iety ( colors4 ,! jasp] 9 ! ,rio ,gr&e gravels is yell[1 r$1 gre51 or v>i\s %ades ( ^! & is commonly susp5d$ z angul> fragm5ts 9 cle> *alc$ony4 ,good agate has also be5 f\nd ne> ,balmorhea 9 ,reeves & ,jeff ,davis c\nties & 9 small] am\nts at num]\s o!r we/ & s\? ,texas localities4 ,agatiz$ wood 7see ,fossil wood1 pp4 #bj-ba74 ,c>nelian 7transluc5t r$di% *alc$ony74--,?is v>iety ( *alc$ony 9 small quantities has be5 report$ f ne> ,van ,horn1 ,hudspe? ,c\nty4 ,small pieces ( c>nelian h be5 f\nd 9 ! gravels ( ! ,rio ,gr&e1 b f9ds h be5 few & scatt]$4 ,jasp] 7impure opaque or subtransluc5t qu>tz74--,good gre51 yell[1 r$1 & br[n jasp] has be5 f\nd 9 ! gravels ( ! ,rio ,gr&e at all ( ! localities t produce agate4 ,! colors are q vivid1 & ! mat]ial takes a f9e poli%4 ,"s pieces ( orbicul> jasp] 7jasp] ) circul> or eye-l m>k+s7 h be5 f\nd 9 ?is mat]ial4 ,^! gravels commonly conta9 jasp] z fragm5ts t are susp5d$ 9 cle> *alc$ony2 ?is is call$ brecciat$ jasp] & yields v h&some cabo*ons4 ,_m ( ! we/ ,texas agate localities also produce jasp] 9 quantity4 ,good jasp] has be5 report$ f nor? ( ,brackettville1 ,k9ney ,c\nty4 ,jasp] is a m9or con/itu5t ( ! /ream gravels 9 _m p>ts ( ! ,/ate4 ,sanid9e ,composition3 ,k,al,si,o2 commonly conta9s "s sodium4 ,cry/al sy/em3 monocl9ic4 ,h>dness3 #f4 ,specific gravity3 #b4eg to #b4eh4 ,lu/]3 vitre\s to pe>ly4 ,color3 colorless1 :ite1 pale yell[1 & gray4 ,/reak3 uncolor$4 ,cleavage3 ?ree directions4 ,fracture3 con*oidal to unev54 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to subtransluc5t4 ,refractive index3 #a4eb to #a4ec4 ,"s feldsp>s1 includ+ sanid9e1 %[ a nice blue %e5 9 reflect$ light p>allel to c]ta9 cry/allographic directions4 ,/ones hav+ ?is prop]ty are call$ moon/one4 ,a cle> yell[i% sanid9e %[+ an attractive blue %e5 has be5 f\nd 9 ,brew/]1 ,jeff ,davis1 & ,presidio c\nties4 ,! individual pieces are small1 ! av]age size be+ ab\t "o-eigh? in*4 ,! sanid9e is f\nd loose 9 ! soil at "s localities :]e x has wea!r$ out ( rhyolite1 & specim5s ( ! sanid9e 9 ! p>5t rock are n difficult to obta94 ,v small cabo*ons c be cut f ?is mat]ial1 b few lapid>ies h done s because inexp5sive l>g] pieces ( moon/one c be obta9$ easily f =eign s\rces4 ,h[ev]1 ! we/ ,texas sanid9e does %[ a blue %e5 :5 cut & poli%$4 ,sp9el ,composition3 ,mg,al,o 7magnesium may be replac$ 9 "p by f]r\s iron or manganese & ! alum9um by f]ric iron & *romium74 ,cry/al sy/em3 isometric4 ,h>dness3 #h4 ,specific gravity3 #c4e to #d4a4 ,lu/]3 vitre\s to sub-metallic4 ,color3 black1 p9k1 r$1 blue1 gre51 yell[1 br[n1 & violet4 ,/reak3 :ite4 ,cleavage3 "o direction1 imp]fect4 ,fracture3 con*oidal4 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to opaque4 ,refractive index3 v>iable1 approximately #a4gb to #b4jj4 ,9 _m areas ( ! _w1 f9e quality1 beautifully color$1 transp>5t sp9els are f\nd & us$ z gems4 ,! only gem-quality sp9el report$ ?us f> 9 ,texas is black & opaque4 ,ne> ,eagle ,flat 9 ,hudspe? ,c\nty1 black sp9el cry/als h be5 f\nd associat$ ) augite & natural glass2 ^! m9]als are wea!r+ out ( an intrusive igne\s rock4 ,! sp9el cry/als h an octah$ral =m :i* is common = ?is m9]al 7fig4 #ag74 ,mo/ ( ! sp9els are free ( flaws1 b because ( _! black color !y h little value z gems4 ,! cry/als are f\nd loose 9 ! s& ( /reams ne> ! outcrops ( ! igne\s rock or emb$d$ 9 ! rock4 ,!y seldom exce$ half an in* 9 diamet]4 ,^! /ones are prim>ily s\ght by collectors4 ,illu/ration3 ,fig4 #ag4 ,common cry/al =m ( sp9el4 ,tektite 7,b$iasite7 ,composition3 ,a natural glass1 approximately #ge ,si,o1 #ae ,al,o1 #d ,fe,o1 also ,mg,o1 ,na,o1 ,k,o1 & traces ( o!r elem5ts4 ,cry/al /ructure3 amorph\s4 ,h>dness3 #e to #f4 ,specific gravity3 #b4cc to #b4dd4 ,lu/]3 vitre\s1 (t5 dull on wea!r$ surfaces4 ,color3 d>k br[n1 gre5i% br[n1 appe>s black 9 ?ick sections4 ,/reak3 uncolor$4 ,cleavage3 none4 ,fracture3 con*oidal4 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to subtransp>5t4 ,refractive index3 #a4dhh to #a4eab4 ,! av]age b$iasite size is ab\t #a in* 9 diamet]1 al?\gh specim5s approximately #c in*es 9 diamet] are kn[n4 ,! uncut tektites are v int]e/+1 %[+ a v>iety ( %apes & surface features 7,pl4 ,v1 ,a7 & _m exhibit contort$ fl[ /ructure4 ,! surface ( _m tektites is groov$ or furr[$1 :ile on o!rs x is smoo? or fro/$4 ,! ,texas tektites are kn[n z 8b$iasites10 aft] place names 9 ,grimes ,c\nty traceable to ! ,b$ias ,indians :o =m]ly liv$ !re4 ,d>k br[n & gre5i%-br[n tektites h be5 f\nd 9 ,texas 9 gravels at scatt]$ localities 9 ,walk]1 ,grimes1 ,brazos1 ,burleson1 ,lee1 ,fayette1 ,gonzales1 ,lavaca1 & ,de,witt c\nties4 ,outside ( ,texas ! only o!r au!nticat$ tektite localities 9 ! ,unit$ ,/ates at ! pres5t "t are 9 ,dodge & ,irw9 c\nties1 ,georgia4 ,a fragm5t ( a simil> tektite has rec5tly be5 report$ f ne> ,m>?a's ,v9ey>d1 ,massa*usetts4 ,! tektites report$ f ,oklahoma are n[ kn[n to be pebbles ( obsidian4 ,al?\gh tektites h little value or beauty z gem/ones1 !y h be5 cut by lapid>ies z bo? facet$ & cabo*on /ones4 ,tektites take a high poli% b are mo/ly s d>k 9 color t !y appe> black4 ,! orig9 ( tektites is ( great sci5tific int]e/ & is curr5tly ! subject ( mu* debate4 ,"s sci5ti/s believe t tektites are ( meteoritic orig91 :ile o!rs believe t tektites 7 =m$ by v>i\s t]re/rial processes4 ,s9ce no "o has actually obs]v$ a tektite to fall or =m1 & _m ( ! !ories ( orig9 are difficult to prove )\t direct obs]vation1 ! orig9 ( tektites is likely to rema9 9 controv]sy = "s "t4 ,topaz ,composition3 ,al7,f1 ,,oh7,si,o4 ,cry/al sy/em3 or?orhombic4 ,h>dness3 #h4 ,specific gravity3 #c4d to #c4f4 ,lu/]3 vitre\s4 ,color3 pale blue1 sky blue1 gre5i%1 :ite1 w9e yell[1 /raw yell[1 grayi%1 p9k1 r$di%1 & orange4 ,/reak3 uncolor$4 ,cleavage3 "o direction1 basal1 highly p]fect4 ,fracture3 con*oidal to unev54 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to subtransluc5t4 ,refractive index3 ab\t #a4fj to #a4fc4 ,disp]sion3 mod]ate4 ,v>i\s yell[ & smoky color$ qu>tz gems are (f]$ = sale z 8,spani% ,topaz10 8,smoky ,topaz10 8,madeira ,topaz10 & 8,topaz ,qu>tz40 ,^! names are entirely mislead+ & %\ld be dropp$ f usage4 ,f9e gem-quality :ite1 pale-blue1 & sky-blue topaz has be5 f\nd ne> ,/reet]1 ,grit1 & ,katemcy1 ,mason ,c\nty4 ,?is ,texas gem mat]ial comp>es favorably 9 color1 size1 & cl>ity ) topaz f\nd any:]e 9 ! ,unit$ ,/ates4 ,f9e cry/als ( topaz 7,pl4 ,v1 ,b1 & fig4 #ah7 occasionally are f\nd 9 pegmatite dikes associat$ ) qu>tz1 black t\rmal9e1 cassit]ite1 & p9k microcl9e4 ,_m ( ! gem-be>+ pegmatites h be5 erod$ away1 leav+ ! topaz conc5trat$ 9 ! /ream b$s4 ,! /ones mo/ly occur z fro/$1 /ream-worn pebbles 7,pl4 ,,vi1 ,a7 9 ! num]\s small creeks 9 ! area4 ,! topaz is heavi] ?an ! qu>tz & microcl9e t compose ! /ream gravel & is commonly f\nd imm$iately on top ( ! granite b$-rock 9 ! bottom ( ! /ream b$4 ,! /ones t5d to lodge beh9d b\ld]s or small dikes cutt+ across ! /ream4 ,illu/ration3 ,fig4 #ah4 ,cry/al faces on topaz cry/al %[n 9 ,plate ,v1 ,b4 ,?is cry/al habit is typical ( ! topaz f ,mason ,c\nty4 ,! :ite or colorless /ones are by f> ! mo/ common1 outnumb]+ ! blui% /ones ab\t t5 to "o4 ,! color ( ! blue /ones t5ds to be irregul>ly di/ribut$ 9 zones p>allel to ! cry/al faces4 ,topaz t is color$ 9 ?is mann] %\ld be cut ) ! be/ blue color ne> ! bottom or culet ( ! gem 7fig4 #ai74 ,if done correctly1 ?is w give ! entire gem/one ! desirable blue color4 ,illu/ration3 ,fig4 #ai4 ,cross section %[+ ! prop] ori5tation ( d>k-color zone 9 a gem cut f an irregul>ly color$ /one4 ,,colorless ,,blue ,! colorless /ones c be turn$ pale yell[1 yell[i% br[n1 or /raw yell[ by exposure to ,x-ray radiation1 & "s ( ! blui% /ones w fluoresce fa9tly yell[i% "u ultra-violet light4 ,! l>ge/ gem-quality topaz cry/al yet f\nd 9 ,nor? ,am]ica has come f ,mason ,c\nty4 ,x is a pale-blue cry/al weigh+ #a1bif grams1 n[ 9 ! collection ( ! ,u4,s4 ,national ,museum4 ,sev]al o!r l>ge pieces1 "s weigh+ ov] a p\nd1 h be5 f\nd4 ,"o l>ge cry/al1 exact weight unkn[n1 0 f\nd ne> ,katemcy4 ,sev]al gem cutt]s h e/imat$ t ?is /one c\ld easily yield a s+le1 flawless pale-blue gem ( ab\t #ejj c>ats4 ,_m l>ge gems h be5 cut f topaz f\nd 9 ?is area1 includ+ at lea/ "o /one ( ov] #cjj c>ats4 ,"o ob/acle 9 ! cutt+ ( topaz is its p]fect basal cleavage4 ,! gem/one %\ld be ori5t$ s t no facet ( ! /one w be p>allel to or )9 less ?an ab\t #e degrees ( ! cleavage direction1 or ! facet may be v difficult or impossible to poli%4 ,x is difficult to e/imate ! productivity ( ?is area s9ce its discov]y 9 ! e>ly #aijj's4 ,few sy/ematic attempts h be5 made to exploit ! deposits1 & a great am\nt ( ! topaz ?us f> recov]$ has be5 f\nd by private collectors4 ,! ,mason ,c\nty topaz deposits are /ill v productive1 & additional exploration may uncov] ev5 m gem-produc+ areas4 ,topaz has also be5 f\nd 9 /ream gravels or pegmatites 9 ,burnet1 ,llano1 ,gillespie1 & ,el ,paso c\nties b v r>ely 9 gem quality4 ,t\rmal9e ,composition3 ,h,al7,b,,oh7,si,o2 hydrog5 (t5 replac$ by iron1 magnesium1 calcium1 or fluor9e4 ,cry/al sy/em3 hexagonal4 ,h>dness3 #g to #g4e4 ,specific gravity3 #b4ih to #c4bj4 ,lu/]3 vitre\s to res9\s4 ,color3 black1 br[ni% black1 br[n1 blue1 gre51 r$1 p9k1 yell[1 & gray4 ,/reak3 uncolor$4 ,cleavage3 two directions1 v imp]fect4 ,fracture3 subcon*oidal to unev54 ,t5acity3 brittle4 ,diaphaneity3 transp>5t to opaque4 ,refractive index3 ab\t #a4fb to #a4fd4 ,black t\rmal9e is s*orl2 br[n t\rmal9e1 dravite4 ,good cry/als ( black & d>k br[n t\rmal9e occur at ,t[n ,m\nta9 ne> ,llano1 ,llano ,c\nty4 ,! t\rmal9e cry/als av]age ab\t #a in* 9 l5g?1 d n commonly exce$ #b in*es1 & are associat$ ) :ite ve9 qu>tz4 ,! qu>tz completely encloses ! t\rmal9e1 b ! cry/als c be brok5 free or ! qu>tz c be trimm$ away ) ! use ( a diamond saw4 ,! latt] proc$ure is recomm5d$ :5ev] possible1 = x is v easy to %att] ! t\rmal9e cry/als :ile try+ to remove !m f ! qu>tz by o!r means4 ,_m ( ! cry/als are completely unsuitable = cutt+1 be+ too brittle or too badly crack$ & flaw$4 ,h[ev]1 "s small cry/als h be5 f\nd t are ( suffici5t quality & size to yield flawless /ones ( a few c>ats4 ,few ( ^! /ones h be5 cut s9ce ! t\rmal9e is s d>k t x appe>s opaque1 & few p]sons f9d a gem ( ?is nature attractive4 ,good black & d>k br[n cry/als ( t\rmal9e associat$ ) &alusite & graphite occur 9 ! ,packsaddle s*i/ 7,precambrian7 ne> ,sunrise ,bea*1 ,llano ,c\nty 7,pl4 ,,vi1 ,b1 & fig4 #bj74 ,al?\gh g5]ally small] 9 diamet] ?an ! cry/als f\nd at ,t[n ,m\nta91 !y commonly exce$ #c in*es 9 l5g?1 al?\gh ! av]age size is a little ov] #a in*4 ,_m ( ^! cry/als are suitable = cutt+ into opaque or ne>ly opaque /ones ( ab\t #e or #f c>ats4 ,black t\rmal9e has also be5 f\nd 9 ,hudspe? & ,culb]son c\nties b n ( suffici5t quality to be us$ z a gem/one4 ,illu/ration3 ,fig4 #bj4 ,common cry/al =m ( ,llano ,c\nty t\rmal9e4 ,turquoise ,composition3 hydr\s phosphate ( alum9um & copp]4 ,cry/al sy/em3 tricl9ic4 ,h>dness3 #e to #f4 ,specific gravity3 v>iable1 #b4f to ab\t #b4h4 ,lu/]3 dull1 sometimes waxy4 ,color3 sky blue to gre5i% blue4 ,/reak3 :ite to gre5i%4 ,cleavage3 none 9 massive mat]ial1 two directions 9 cry/als4 ,fracture3 con*oidal to subcon*oidal4 ,t5acity3 brittle4 ,diaphaneity3 subtransluc5t to opaque4 ,refractive index3 #a4fa to #a4fe4 ,turquoise ( good sky-blue to gre5i%-blue color has be5 f\nd a few miles s\?we/ ( ,van ,horn1 ,culb]son ,c\nty4 ,sev]al %all[ pits 7 dug at ?is locality ab\t #aiaj2 h[ev]1 ! am\nt ( turquoise produc$ 0 small4 ,! ma9 occurr5ce ( ! turquoise 0 9 seams ab\t #a millimet] ?ick along jo9ts 9 ! f9e-gra9$ rocks ( ?is area4 ,p]sons :o h visit$ ,culb]son ,c\nty m rec5tly report t ev5 m9ute traces ( ! turquoise are n[ difficult to f9d at ! old prospect pits4 ,h[ev]1 fur!r prospect+ 9 ! area might yield "s additional localities4 ,small am\nts ( turquoise h be5 report$ ne> ,el ,paso1 ,el ,paso ,c\nty1 & also 9 volcanic rocks ne> ! ,jeff ,davis-,brew/] ,c\nty l9e1 nor? ( ,alp9e4 ,a small am\nt ( turquoise has be5 m9$ f sev]al localities a few miles nor?we/ ( ,si]ra ,blanca 9 ! ,si]ra ,blanca ,m\nta9s ( ,hudspe? ,c\nty4 ,,gloss>y ,amorph\s--)\t def9ite molecul> /ructure2 n cry/all9e4 ,b>oque /one--an irregul>ly %ap$1 poli%$ /one2 usually appli$ to tumbl$ /ones4 ,b>oque pe>l--an irregul>ly %ap$ pe>l4 ,brilliancy--reflect+ mu* light2 hav+ brightness4 ,brilliant cut--a mode ( arrangem5t ( facets commonly us$ on r\nd or oval /ones4 ,! /&>d ,am]ican brilliant cut has #eg or #eh facets4 ,mo/ diamonds ( #e or less c>ats are cut 9 ?is mann]4 ,cabo*on--a /one cut ) a flat or convex upp] surface2 sometimes facet$ 9 "p4 ,opal1 /> sapphire1 & agate are /ones t are frequ5tly cut 9 ?is /yle 7fig4 #b74 ,cambrian--a division ( geologic "t1 e/imat$ to be ! "t f #eej to #ddj million ye>s ago2 ! olde/ "t division ( ! ,paleozoic era4 ,c>at--a unit ( weight equal to ( a gram or #j4b gram4 ,"o ounce avoirdupois is equal to #ada4ge c>ats4 ,cleavage--! t5d5cy ( c]ta9 m9]als to split 9 p>ticul> directions yield+ relatively smoo? plane surfaces4 ,con*iol9--an organic album9oid sub/ance f\nd 9 pe>ls4 ,con*oidal--a type ( fracture hav+ curv$ concavities or ! approximate %ape ( "o-half ( a bivalve %ell4 ,glass has excell5t con*oidal fracture4 ,cretace\s--a division ( geologic "t1 e/imat$ to be ! "t f #ace to #fj million ye>s ago2 y\nge/ division ( ! ,mesozoic era4 ,cr[n--t portion ( a facet$ gem above ! girdle2 ! upp] portion ( a facet-cut gem 7fig4 #f74 ,cryptocry/all9e--compos$ ( v f9e or microscopic cry/als4 ,cry/al--! regul> polyh$ral =m1 b\nd$ by plane surfaces1 t is assum$ by a m9]al "u suitable conditions4 ,cry/als h def9ite ext]nal symmetry & int]nal molecul> ord]4 ,cry/all9e--possess+ def9ite int]nal molecul> ord]2 n amorph\s4 ,cubic--9 ! g5]al %ape ( a cube4 ,! isometric cry/al sy/em is (t5 call$ ! cubic sy/em4 ,culet--! v bottom portion ( a facet$ gem2 ! po9t or l9e =m$ by ! int]section ( ! l[e/ pavilion facets 7fig4 #f74 ,d5dritic--bran*+ or tree-l 9 =m4 ,diaphaneity--relative transp>5cy4 ,! diaphaneity ( a m9]al is describ$ z transp>5t1 transluc5t1 opaque1 etc4 ,dike--a tabul> rock body1 usually igne\s 9 orig91 :i* cuts across ! surr\nd+ rock /rata4 ,disp]sion--a measure ( ! ability ( gem/ones to sep>ate complex or :ite light into its compon5t colors2 (t5 illu/rat$ ) a prism4 ,gem/ones t are capable ( sep>at+ colors ( light widely are said to h high disp]sion2 gem/ones n s capable ( sep>at+ :ite light into colors are said to h l[ disp]sion4 ,dopp+--! act ( cem5t+ a gem/one1 ei!r r\gh or p>tly f9i%$1 to a dop-/ick4 ,dop-/ick--! wood5 /ick or cyl9drical piece ( metal to :i* a gem/one is cem5t$ to facilitate h&l+ dur+ cutt+ & poli%+4 ,dop-wax--! ag5t or cem5t us$ to secure a gem/one to a dop-/ick4 ,em]ald cut--a rectangul> or squ>e facet$ /one ) bevel$ corn]s ^: surfaces are cov]$ ) sev]al s]ies ( rectangul> facets4 ,eoc5e--a division ( geologic "t1 e/imat$ to be ! "t f #ej to #dj million ye>s ago2 "o ( ! old] divisions ( ! ,c5ozoic era4 ,extrusive rock--igne\s rock t has be5 extrud$ or =c$ out onto ! e>?'s surface4 ,facet--a s+le plane poli%$ surface on a facet$ gem4 ,facet head--a device us$ 9 ! cutt+ & poli%+ ( facet$ gems2 us$ to control ! placem5t ( facets & _! relative angles 7fig4 #g74 ,facet table--! equipm5t us$ 9 ! cutt+ & poli%+ ( facet$ gems & ! table on :i* mo/ ( ! equipm5t is m\nt$ 7fig4 #g74 ,feldsp>--a gr\p ( closely relat$ silicate m9]als includ+ or?oclase1 microcl9e1 sanid9e1 plagioclase1 labradorite1 & o!rs4 ,fire--! reflections ( v>i\sly color$ light f a preci\s opal2 also ! diff]5t colors ( light reflect$ f a facet$ gem ow+ to ! disp]sion ( ! m9]al4 ,fracture--! texture ( a fre%ly brok5 surface o!r ?an a cleavage surface1 describ$ z con*oidal1 ev51 spl9t]y1 etc4 ,gem--a cut & poli%$ gem/one4 ,gemology--! sci5ce deal+ ) ! /udy ( gem/ones4 ,gem/one--a m9]al suitable = cutt+ into a gem2 ! t]m gem/ones is frequ5tly us$ collectively to include bo? cut & poli%$ /ones & r\gh /ones4 ,geode--a r\nd$ or sph]ical rock cavity2 commonly l9$ ) cry/als4 ,girdle--! portion ( a facet$ gem sep>at+ ! cr[n f ! pavilion2 ! girdle may or may n be poli%$ & usually conta9s ab\t #b p]c5t ( ! total dep? ( ! gem 7fig4 #f74 ,gneiss--a co>se-gra9$ metamorphic rock hav+ segregations ( granul> & platy m9]als t give x a m or less b&$ appe>ance )\t well-develop$ s*i/osity4 ,gra9 7pe>l gra97--a unit ( weight equal to #j4je gram or #j4be c>at2 n ! same z ! ,troy gra94 ,granite--a granul> igne\s rock compos$ mo/ly ( qu>tz1 feldsp>1 & commonly mica &_/or hornbl5de4 ,hexagonal--hav+ six angles & six sides2 a cry/al sy/em 9 :i* ! cry/al faces are ref]r$ to f\r int]sect+ axes2 ?ree ( ^! axes are equal1 lie 9 ! same plane1 & int]sect at angles ( #fj degrees2 ! f\r? axis is p]p5dicul> to ! o!r ?ree4 ,igne\s rock--rock =m$ by solidification f a hot melt4 ,index ( refraction--a measure ( ! relative ability ( a gem/one to 8b5d0 incid5t light rays2 s9e ( ! angle ( incid5ce ( a light ray divid$ by ! s9e ( ! angle ( refraction4 ,intrusive rock--rock t has be5 pu%$ 7usually 9 a molt5 /ate7 among pre-exi/+ rock /rata1 commonly along faults or fissures4 ,intrusive rocks d n rea* ! e>?'s surface b are commonly expos$ at ! surface by lat] erosion4 ,isometric--a cry/al sy/em 9 :i* ! cry/al faces are ref]r$ to ?ree equal int]sect+ axes at "r angles to ea* o!r4 ,lap--a disc-%ap$ piece ( metal or o!r mat]ial :i* is impregnat$ ) diamond du/1 or "s o!r cutt+ or poli%+ ag5t1 t is revolv$ :ile ! gem/one is work$ aga9/ x4 ,lap plate--a metal plate to :i* a cutt+ or poli%+ lap is atta*$1 usually by means ( a ?read$ bolt & w+ nut4 ,! lap plate is atta*$ to ! %aft :i* is turn$ by ! motor "u ! facet table4 ,lapid>y--"o :o practices ! lapid>y arts2 a gem cutt]4 ,lime/one--a s$im5t>y rock compos$ mo/ly ( calcium c>bonate4 ,lu/]--! appe>ance ( ! fre%ly brok5 or unwea!r$ surface ( a m9]al 9 reflect$ light 7p4 #e74 ,ma9 facet--z appli$ to ! /&>d ,am]ican brilliant cut1 "o ( ! fir/ eight facets cut on ei!r ! cr[n or pavilion ( a gem 7fig4 #f74 ,matrix--! mat]ial 9 :i* a specific m9]al is emb$d$2 also ! rock to :i* "o end ( a cry/al is atta*$4 ,metamorphic rock--rock t has be5 *ang$ f its orig9al /ate by heat1 pressure1 *emical action1 or "s comb9ation ( ^! factors4 ,millimet]--_/ c5timet]2 approximately _/ in*4 ,m9]alogy--! sci5ce conc]n$ ) ! /udy ( m9]als1 includ+ _! occurr5ce1 composition1 =ms1 prop]ties1 & /ructure4 ,monocl9ic--a cry/al sy/em 9 :i* ! cry/al faces are describ$ 9 relation to ?ree int]sect+ unequal axes1 two ( :i* are at "r angles & ! ?ird incl9$4 ,oligoc5e--a division ( geologic "t1 e/imat$ to be ! "t f #dj to #bh million ye>s ago2 "p ( ! ,c5ozoic era4 ,opaque--does n transmit light4 ,orbicul>--conta9+ orbs or sph]ical or eye-l m>k+s or /ructures4 ,or?orhombic--a cry/al sy/em 9 :i* cry/al faces are ref]r$ to ?ree unequal int]sect+ axes at "r angles4 ,pavilion--! portion ( a facet$ gem bel[ ! girdle 7fig4 #f74 ,pegmatite--a body ( co>se-gra9$ intrusive igne\s rock1 commonly l5s or dike %ap$4 ,p]?itic--a plaid-patt]n$ /ructure result+ f int]mixture ( soda- & pota%-ri* feldsp>s4 ,phantom cry/al--a cry/al outl9e se5 )9 ano!r cry/al1 mo/ly due to entrapp+ ( inclusions dur+ ! cry/al's gr[?4 ,pleo*roism--! prop]ty ( transmitt+ diff]5t colors ( light 9 diff]5t cry/allographic directions4 ,po9t--a unit ( weight equal to _/ 7#j4ja7 c>at4 ,por\s--conta9+ pores or void spaces4 ,precambrian--a division ( geologic "t1 e/imat$ to be all ( geologic "t prior to #eej million ye>s ago2 ! "t be=e ! ,paleozoic era4 ,pre=m--a gem/one t has be5 gr\nd to a r\gh outl9e ( ! f9i%$ %ape ( a gem4 ,rhyolite--a f9e-gra9$ extrusive or %all[ intrusive igne\s rock ( approximately ! same composition z granite4 ,r\gh--uncut1 n work$ by a lapid>y1 n cut & poli%$4 ,s*i/--a metamorphic rock t conta9s an abundance ( ori5t$ platy m9]als t enable ! rock to be split ) relative ease p>allel to ! flat surfaces ( ! platy m9]als4 ,silicifi$--replac$ by or conta9+ a l>ge am\nt ( qu>tz or silica4 ,skill facet--a t]m (t5 us$ = ! pavilion girdle facets ( ! /&>d ,am]ican brilliant cut 7fig4 #f74 ,specific gravity--! weight 9 air divid$ by ! loss ( weight 9 wat] at a giv5 temp]ature1 or ! weight ( an object 9 air divid$ by ! weight ( an equal volume ( wat]2 also call$ relative d5sity2 ! mo/ commonly us$ /&>d temp]ature = ?is measurem5t is #d ,c4 or #ci4b ,f4 ,/> facet--"o ( ! eight facets surr\nd+ ! table facet ( a /&>d ,am]ican brilliant cut 7fig4 #f74 ,/ep cut--a mode ( facet+ 9 :i* ! surface ( ! gem is cov]$ by a s]ies ( squ>e or rectangul> facets2 /ones ?usly cut are usually squ>e1 rectangul>1 or irregul> ) /raight sides 9 outl9e4 ,/reak--! color ( a m9]al :5 f9ely p[d]$2 usually det]m9$ by rubb+ ! m9]al aga9/ a piece ( unglaz$ porcela94 ,symmetry--! numb]1 location1 & balanc$ arrangem5t ( cry/al faces 9 ref]5ce to ! cry/allographic axes or o!r cry/allographic planes or directions4 ,syn!tic gem--a gem/one manufactur$ by man t has approximately ! same *emical composition & prop]ties z a natural gem/one4 ,table facet--! l>ge horizontal facet f\nd on ! cr[n ( _m gems1 (t5 call$ simply ! table 7fig4 #f74 ,t5acity--! resi/ance ( m9]als to breakage1 describ$ by su* t]ms z malleable1 ductile1 sectile1 & brittle 7p4 #f74 ,t]m9ation--! end ( a cry/al t is completely enclos$ by cry/al faces1 ! cry/al end t is n atta*$ to ! matrix4 ,t]ti>y--a division ( geologic "t1 e/imat$ to be ! "t f #fj to #a million ye>s ago2 ! ,t]ti>y includes ! ,paleoc5e1 ,eoc5e1 ,oligoc5e1 ,mioc5e1 & ,plioc5e epo*s 7f olde/ to y\nge/74 ,tetragonal--hav+ f\r angles2 a cry/al sy/em 9 :i* ! cry/al faces are ref]r$ to ?ree axes at "r angles to ea* o!r1 two ( :i* are equal & ! ?ird long] or %ort]4 ,transluc5t--all[+ ! passage ( light b diffus+ x suffici5tly s t objects on ! o!r side _c be cle>ly di/+ui%$4 ,transp>5t--cle>1 all[+ free passage ( light s t objects on ! o!r side c be readily di/+ui%$2 opposite ( opaque4 ,tricl9ic--a cry/al sy/em 9 :i* ! cry/al faces are ref]r$ to ?ree unequal axes1 none ( :i* are at "r angles4 ,tumbl+--a process ( poli%+ irregul>ly %ap$ gem/ones 7p4 #ag74 ,ve9--a tabul>1 irregul>1 or twi/+ m9]al deposit t is ?9 9 relation to its l5g? & bread?1 usually ! result ( solution or hydro!rmal activity4 ,vitre\s--hav+ lu/]1 g5]al appe>ance1 or physical prop]ties simil> to glass4 ,vug--an unfill$ rock cavity1 commonly l9$ ) cry/als2 may lat] become fill$ by m9]als ow+ to solution or hydro!rmal activity4 ,,select$ ,,ref]5ces ,&]son1 ,b4 ,w4 7#aidh7 ,gem te/+3 ,em]son1 ,new ,york4 ,bak]1 ,c4 ,l4 7#aice7 ,metallic & non-metallic m9]als & ores 7preci\s /ones71 9 ,! geology ( ,texas1 ,vol4 ,,ii1 ,/ructural & economic geology3 ,univ4 ,texas ,bull4 #cdja1 ,jan4 #a1 #aicd1 pp4 #efh-efi4 ,b>nes1 ,v4 ,e4 7#aidj7 ,nor? ,am]ican tektites3 ,univ4 ,texas ,pub4 #cide1 ,dec4 #a1 #aici1 pp4 #dgg-ehb4 ,dake1 ,h4 ,c41 ,fle5]1 ,f4 ,l41 & ,wilson1 ,b4 ,h4 7#aich7 ,qu>tz family m9]als3 ,:ittlesey ,h\se1 ,mc,graw-,hill ,book ,company1 ,inc41 ,new ,york4 ,=d1 ,w4 ,e4 7#aicb7 ,a textbook ( m9]alogy 7#d? ed473 ,john ,wiley & ,sons1 ,inc41 ,new ,york4 ,kraus1 ,e4 ,h41 & ,slawson1 ,c4 ,b4 7#aidg7 ,gems & gem mat]ials 7#e? ed473 ,mc,graw-,hill ,book ,company1 ,inc41 ,new ,york4 ,kunz1 ,g4 ,f4 7#ahib7 ,gems & preci\s /ones ( ,nor? ,am]ica 7#b;d ed473 ,sci5tific ,publi%+ ,company1 ,new ,york4 ,p\gh1 ,f4 ,h4 7#aiec7 ,a field guide to rocks & m9]als3 ,h\ghton ,miffl9 ,company1 ,bo/on4 ,simpson1 ,b4 ,w4 7#aieh7 ,gem trails ( ,texas3 ,granbury1 ,texas4 ,s9kankas1 ,john 7#aiee7 ,gem cutt+3 ,d4 ,van ,no/r& ,company1 ,inc41 ,pr9ceton1 ,new ,j]sey4 ---- 7#aiei7 ,gem/ones ( ,nor? ,am]ica3 ,d4 ,van ,no/r& ,company1 ,inc41 ,pr9ceton1 ,new ,j]sey4 ,smi?1 ,g4 ,f4 ,h4 7#aieh7 ,gem/ones 7#ac? ed471 revis$ by ,f4 ,c4 ,phillips3 ,me?u5 & ,company1 ,ltd41 ,london4 ,sp]is51 ,f4 ,j4 7#aiej7 ,! art ( ! lapid>y3 ,! ,bruce ,publi%+ ,company1 ,milwaukee1 ,wiscons94 ,/]rett1 ,d4 ,b4 7#aiac7 ,gems & preci\s /ones1 9 ,m9]al res\rces ( ! ,unit$ ,/ates1 ,cal5d> ,ye> #aiab1 ,"p ,,ii1 ,non-metals3 ,u4 ,s4 ,geol4 ,survey1 pp4 #ajbc-ajfj4 ,plate ,i ,illu/ration3 ,a ,gem-quality cele/ite cry/als f ,travis ,c\nty1 ,texas4 ,twice natural size4 ,l[] portion ( ! cry/als is colorless2 ! tips are d>k blue4 ,illu/ration3 ,b ,opaliz$ wood f ! ,texas ,gulf ,coa/al ,pla94 ,specim5 at left is ri* br[n & tan2 specim5 at "r is fossil palm wood & is black1 r$di% br[n1 & :ite4 ,"o-?ird natural size4 ,plate ,,ii ,illu/ration3 ,a ,gem-quality g>net cry/als & facet$ gem f ,gillespie ,c\nty1 ,texas4 ,natural size4 ,illu/ration3 ,b ,labradorite f ,brew/] ,c\nty1 ,texas4 ,bo? /ones are pale yell[4 ,"o & a half times natural size4 ,plate ,,iii ,illu/ration3 ,a ,p9k microcl9e cry/al f ,burnet ,c\nty1 ,texas4 ,illu/ration3 ,b ,smoky qu>tz f ,burnet ,c\nty1 ,texas4 ,natural size4 ,colorless cry/al at c5t] back is includ$ = color comp>ison4 ,plate ,,iv ,illu/ration3 ,poli%$ agate f gravels ( ! ,rio ,gr&e ne> ,zapata1 ,zapata ,c\nty1 ,texas4 ,b&s are blue & gray2 o!r inclusions are br[n1 yell[1 & r$di%4 ,"o & a half times natural size4 ,plate ,v ,illu/ration3 ,a ,texas tektites 7b$iasites7 %[+ v>iety ( surface features4 ,natural size4 ,illu/ration3 ,b ,topaz cry/al f a pegmatite dike ne> ,/reet]1 ,mason ,c\nty1 ,texas4 ,natural size4 ,measurem5ts3 #a by #a by #c in*es2 weight3 #aid grams 7#igj c>ats72 pale blue2 mo/ly gem quality4 ,plate ,,vi ,illu/ration3 ,a ,topaz f /ream gravels ne> ,/reet]1 ,mason ,c\nty1 ,texas4 ,natural size4 ,left to "r3 colorless worn pebble2 em]ald-cut pale-blue topaz1 weight #aj c>ats2 pale-blue worn pebble1 weight #bje c>ats2 /ep out sky-blue topaz1 weight #ac c>ats2 pale-blue worn pebble4 ,illu/ration3 ,b ,t\rmal9e cry/als 9 s*i/ f ,llano ,c\nty1 ,texas4 ,index ,a act9olite3 #bf agate3 #bj1 #bh1 #ch agatiz$ wood3 #bg allanite3 #ba alm&ite3 #bb amazonite3 #bc amazon /one3 #bc amb]3 #ah ame?y/3 #be ,ame?y/ ,hill3 #be amorph\s gem/ones3 #i &alusite3 #cj ,arkansas3 #ai ,arm/rong ,c\nty3 #ba augite3 #ah1 #bh ,b ,b>+] ,hill1 ,llano ,c\nty3 #ba1 #bf b>oque pe>ls &_/or /ones3 #ag1 #be b$iasite 7tektite73 #bh-bi1 #ci b]yl3 #ah ,big ,b5d ,national ,p>k3 #bg biotite3 #bc ,blanco ,c\nty3 #ah1 #bb ,brazos ,c\nty3 #bi ,brazos ,riv]3 #be ,brew/] ,c\nty3 #ah1 #bc1 #bd1 #be1 #bf1 #bg1 #bh1 #ca1 #cf brilliancy3 #e brilliant cut1 /&>d ,am]ican3 #ac1 #ae1 #af ,br[n ,c\nty3 #ai ,burleson ,c\nty3 #bi ,burnet ,c\nty3 #bj1 #bb1 #bc1 #be1 #bf1 #cj1 #cg ,c cabo*on gems3 #aj-ab ,caddo ,lake3 #be c>buncle3 #bb c>nelian3 #bg cassit]ite3 #bc1 #bi cele/ite3 #ai1 #ce *alc$ony3 #bg geodes3 #bf *uck3 #ae1 #ag citr9e3 #be-bf cleavage3 #f1 #ac coal3 #bb ,coke ,c\nty3 #ai color3 #e ,colorado ,riv]3 #be ,con*o ,riv]3 #be cr[n girdle facets3 #af1 #ag cr[n ( gem/one3 #ae1 #af cry/als3 #g-i cry/al sy/ems3 #g crytolite3 #ba ,culb]son ,c\nty3 #bb1 #bc1 #be1 #bf1 #ca culet3 #ac cutt+ & poli%+3 #aj-ag cutt+ lap3 #ac ,d ,de,witt ,c\nty3 #bi diamond3 #ai saw3 #aj1 #aa diaphaneity3 #e disp]sion3 #f dopp+3 #ab1 #ac dop-/ick3 #ab1 #ae1 #ag dop-wax3 #ab1 #ae1 #ag dravite3 #cj durability3 #f ,duval ,c\nty3 #ba1 #bd ,e ,el ,paso ,c\nty3 #bb1 #cj1 #ca em]ald cut3 #ae epidote3 #ai-bj ,f facet1 k9ds (3 #ac ma93 #af skill3 #af table3 #ac1 #ad facet$ gems &_/or /ones3 #aj1 #ac-ag ,fayette ,c\nty3 #bj1 #bi f]gusonite3 #ba fire3 #e ,fi%] ,c\nty3 #ai fluorite3 #bj1 #ba ,fo>d ,c\nty3 #ai fossil wood3 #bj-ba1 #bb fracture3 #f ,frankl9 ,m\nta9s3 #ah ,g gadol9ite3 #ba-bb g>net3 #bj1 #bb1 #cf gem/ones1 by k9ds3 #ah-ca geodes1 cele/ite3 #ai ,georgia3 #bi ,gillespie ,c\nty3 #ah1 #bb1 #bc1 #be1 #bf1 #cj1 #cf girdle facets3 #af gneiss3 #bb ,gonzales ,c\nty3 #bj1 #bi gra93 #be gram3 #g graphite3 #cj ,grimes ,c\nty3 #bi gr9d+3 #ab ,guadalupe ,riv]3 #be ,gulf ,coa/3 #be ,gulf ,coa/al ,pla93 #ah1 #bj1 #bb1 #ce ,h h>dness3 #f ,hudspe? ,c\nty3 #ah1 #bj1 #bb1 #bd1 #be1 #bf1 #bg1 #bh1 #ca ,i index ( refraction3 #e ,j jasp]3 #bg-bh ,jeff ,davis ,c\nty3 #bf1 #bg1 #bh1 #ca jet3 #bb ,k ,k9ney ,c\nty3 #bh ,l labradorite3 #bc1 #cf ,lake ,bu*anan3 #ba ,lampasas ,c\nty3 #ai lap plate3 #ac ,lavaca ,c\nty3 #bi ,lee ,c\nty3 #bj1 #bi lignite3 #bb ,live ,oak ,c\nty3 #ba ,llano ,c\nty3 #ah1 #ai1 #bj1 #ba1 #bb1 #bc1 #be1 #bf1 #cj1 #ca1 #dj ,llano ,riv]3 #be lu/]3 #e ,m ,madeira topaz3 #bi ,mason ,c\nty3 #bj1 #bb1 #bc1 #bf1 #bi1 #cj1 #ci1 #dj ,massa*usetts3 #bi ,mav]ick ,c\nty3 #ah microcl9e3 #bj1 #ba1 #bc-bd1 #bi1 #cg ,mohs scale ( h>dness3 #f moon/one3 #bh ,m\nt ,bonnell3 #ai muscovite3 #bc ,n natural glass3 #ah1 #bd1 #bh ,ne$le ,peak1 ,presidio ,c\nty3 #bg niv5ite3 #ba ,nolan ,c\nty3 #ai ,nueces ,riv]3 #be ,o obsidian3 #bd1 #bi ,oklahoma3 #bi opal3 #bj1 #bd opaliz$ wood3 #ce orbicul> jasp]3 #bh ounce3 #g ,p ,packsaddle ,m\nta93 #bc ,packsaddle s*i/3 #cj palm wood3 #ba1 #ce ,palo ,duro ,canyon3 #ba pavilion3 #ac1 #af facets3 #af girdle facets3 #af1 #ag pe>l3 #bd-be pegmatites &_/or pegmatite dikes3 #ah1 #bj1 #ba1 #bb1 #bc1 #bf1 #bi1 #ci petrifi$ wood3 #bf phantom cry/als3 #bf pi/acite3 #bj pleo*roism3 #e po9t3 #g poli%+3 #ag lap3 #ac1 #af pre=m$ /one3 #af pre=m+3 #ae ,presidio ,c\nty3 #bj1 #bb1 #bd1 #be1 #bf1 #bg1 #bh prop]ties ( gem/ones3 #e-g ,q qu>tz3 #bj1 #ba1 #bc1 #be-bh1 #bi1 #cj smoky3 #ch ,r radioactive elem5ts3 #bb radioactivity ( gadol9ite3 #ba r>ity3 #f ,reeves ,c\nty3 #bf1 #bg ,rio ,gr&e3 #be gravels (3 #ba1 #bg1 #ch ,valley3 #bg rock cry/al3 #bf rose qu>tz3 #bf ,s ,sab9e ,riv]3 #be s&+3 #ab sanid9e3 #bh saw+3 #aj s*eelite3 #bj s*orl3 #cj size3 #g 8skill0 facets3 #af 8slab0 ( gem mat]ials3 #aa ,smi?sonian ,in/itution3 #ba smoky qu>tz3 #bc1 #bf1 #cg smoky topaz3 #bi ,spani% topaz3 #bi specific gravity3 #g sp9el3 #ah1 #bh /> facets3 #ag /ep cut3 #ae /reak3 #f syn!tic gems3 #g ,t table facet3 #ac1 #ae tektite 7b$iasite73 #bh-bi1 #ci t5acity3 #f ?orogummite3 #ba topaz3 #bc1 #bf1 #bi-cj1 #ci1 #dj qu>tz3 #bi t\rmal9e3 #bf1 #bi1 #cj-ca1 #dj ,t[n ,m\nta91 ,llano ,c\nty3 #bf1 #cj transp>5cy3 #f ,travis ,c\nty3 #ai1 #ce ,tr9ity ,riv]3 #be tumbl$ gems3 #ag turquoise3 #ca ,u ,u4 ,s4 ,national ,museum3 #cj ,v value ( gem/ones3 #f1 #g ,val ,v]de ,c\nty3 #bd valv]dites3 #bd ,van ,horn1 ,hudspe? ,c\nty3 #bg ,w ,walk] ,c\nty3 #bi ,wa%+ton ,c\nty3 #bj ,webb ,c\nty3 #ba weight1 units (3 #g1 #be ,z ,zapata ,c\nty3 #ch ,transcrib]'s ,notes --,sil5tly correct$ a few typos4 --,r5umb]$ figures #f & #g 7& ref]5ces to !m7 to correspond to _! ord] 9 ! pr9t$ book4 --,reta9$ publication in=mation f ! pr9t$ edition3 ?is e,book is public-doma9 9 ! c\ntry ( publication4 --,9 ! text v]sions only1 text 9 italics is delimit$ by und]scores4