,libr>ies47 ,,! ,,*emi/ry1 ,,prop]ties ,,& ,,te/s ,,( ,,preci\s ,,/ones 99 99 99 99 99 ,,by ,,! ,,same ,,au?or ,,! ,,/ol5 ,,planet4 7#bnd edition47 #cs4 #f;d4 ,,?r\gh ,,! ,,sun ,,9 ,,an ,,air%ip4 #fs4 ,,! ,,immortal ,,light4 7#bnd edition47 #fs4 ,c4 ,,griff9 ,,& ,,co41 ,,ltd4 ,,! ,,autobiography ,,( ,a ,,picture4 7#bnd edition47 #cs4 #f;d4 ,,?is ,,workaday ,,_w4 7,9 ! ,press47 ,,h5ry ,j4 ,,drane4 ,,pepp]',s ,,boy',s ,,playbook ,,( ,,sci5ce4 7,new edition47 ,n[ 9 ,press1 revis$1 re-writt5 & re-illu/rat$ by ,,dr4 ,,john ,,ma/94 ,,george ,,r\tl$ge ,,& ,,sons1 ,,ltd4 ,,etc4 ,,etc4 99 99 99 99 99 ,,! ,,*emi/ry1 ,,prop]ties ,,& ,,te/s ,,( ,,preci\s ,,/ones4 ,,by ,,john ,,ma/91 ,m4,a4 ,d4,,sc4 ,,ph4,d4 ,,litt4,d4 ,f4,s ,a4,,scot4 ,f4,l4,s4 ,f4,c4,s4 ,f4,r4,a4,s4 ,f4,r4,m4,s4 ,r4,b4,a4 ,au?or ( ,p>asites ( ,insects1 ,! ,true ,analysis ( ,milk1 ,plate-,culture & ,/a9+ ( ,amoebae1 etc41 etc4 ,london ,e4 ,f4 ,n4 ,,spon1 ,,limit$1 #eg ,,haym>ket ,,new ,,york ,,spon ,,*amb]la91 #abc ,,lib]ty ,,/reet #aiaa ,transcrib]'s note3 ,= ,text3 ,a ^w surr\nd$ by a c$illa su* z ?is signifies t ! ^w is bold$ 9 ! text4 ,a ^w surr\nd$ by und]scores l ?is signifies ! ^w is italics 9 ! text4 ,! italic & bold m>kup = s+le italiz$ lett]s or =eign abbreviations are delet$ = easi] read+4 ,= numb]s & equations3 ,p>5!ses h be5 add$ to cl>ify fractions4 ,und]scores be=e bracket$ numb]s 9 equations d5ote a subscript4 ,,cont5ts ,,*apt] ,,page ,i ,,introductory #a ,,ii ,,! ,,orig9 ,,( ,,preci\s ,,/ones #g ,,iii ,,physical ,,prop]ties--7,a7 ,,cry/all9e ,,/ructure #ac ,,iv 7,b7 ,,cleavage #ai ,v 7,c7 ,,light #bf ,,vi 7,d7 ,,col\r #cb ,,vii 7,e7 ,,h>dness #ci ,,viii 7,f7 ,,specific ,,gravity #de ,,ix 7,g7 ,,heat #eb ,x 7,h7 ,,magnetic ,,& ,,electric ,,influ5ces #eg ,,xi ,,! ,,cutt+ ,,( ,,preci\s ,,/ones #fb ,,xii ,,imitations1 ,,& ,,"s ,,( ,,! ,,te/s ,,( ,,preci\s ,,/ones #gj ,,xiii ,,v>i\s ,,preci\s ,,/ones #hj ,,xiv 7cont9u$7 #hh ,,xv #ih ,,preface ,"s little "t ago c]ta9 ,london diamond m]*ants & :olesale deal]s 9 preci\s /ones made ! sugge/ion to me to write a "w on ?is section ( m9]alogy1 z !re did n appe> to be any giv+ exactly ! in=mation mo/ ne$$4 ,f9d+ !re 0 a call = su* a book ,i h writt5 ! pres5t volume 9 ord] to meet ?is want1 & ,i tru/ t ?is h&book w prove useful1 n only to ! exp]t & to ^? requir+ c]ta9 te*nical in=mation1 b also to ! g5]al public1 ^: int]e/ 9 ?is entranc+ subject may be simply t ( pleasure 9 ! pur*ase1 possession1 or collection ( preci\s /ones1 or ev5 9 ! m]e exam9ation ( !m ?r\gh ! plate-glass ( a jewell]'s w9d[4 ,,john ,,ma/94 ,,totley ,,brook1 ,,ne> ,,%effield4 ,june #aiaa4 ,,! ,,*emi/ry1 ,,prop]ties ,,& ,,te/s ,,( ,,preci\s ,,/ones ,,*apt] ,i4 ,,introductory4 ,:at con/itutes a preci\s /one is ! "q :i*1 at ! onset1 rises 9 ! m9d1 & ?is "q1 simple z x seems1 is "o by no means easy to answ]1 s9ce :at may be consid]$ preci\s at "o "t1 may cease to be s at ano!r4 ,!re are1 h[ev]1 c]ta9 m9]als :i* possess di/9ctive features 9 _! qualities ( h>dness1 col\r1 transp>5cy1 refractability or d\ble refractability to light-beams1 :i* qualities place !m 9 an entirely diff]5t class to ! m9]als ( a metallic nature4 ,^! p>ticul> & non-metallic m9]als1 !re=e1 because ( _! comp>ative r>ity1 rise pre-em95tly above o!r m9]als1 & become actually preci\s4 ,?is is1 at ! same "t1 b a comp>ative t]m1 = x w readily be und]/ood t 9 ! case ( a sudd5 flood+ ( ! m>ket ) "o class ( /one1 ev5 if x %\ld be "o hi!rto r>e & preci\s1 !re w\ld be an equally sudd5 drop 9 ! intr9sic value ( ! jewel to su* an ext5t z p]haps to wipe x out ( ! category ( preci\s /ones4 ,= in/ance1 rubies 7 discov]$ long be=e diamonds2 !n :5 diamonds 7 f\nd ^! 7 consid]$ mu* m valuable till _! abundance made !m common1 & !y became ( little acc\nt4 ,rubies aga9 ass]t$ _! position z *ief ( all preci\s /ones 9 value1 & 9 _m biblical ref]5ces rubies are quot$ z be+ ! symbol ( ! v acme ( weal?1 su* z 9 ,prov]bs1 *apt] iii41 v]ses #ac & #ae1 :]e !re are ! passages1 happy is ! man t f9de? wisdom 444 %e is m preci\s ?an rubies--& ?is1 not)/&+ ! enorm\s quantity ( !m at t "t obta9$ f ! ruby m9es ( ,ophir & ,nubia1 :i* 7 !n ! *ief s\rces ( weal?4 ,x w also be rememb]$ t ,josephus relates h[1 at ! fall ( ,j]usalem1 ! spoil ( gold 0 s great t ,syria 0 inundat$ ) x1 & ! value ( gold !re quickly dropp$ to "o-half2 o!r hi/orians1 also1 speak+ ( ?is "t1 record su* a glut ( gold1 silv]1 & jewels 9 ,syria1 z made !m ( little value1 :i* /ate cont9u$ = "s consid]able p]iod1 till ! untold weal? became ru?lessly & wa/efully scatt]$1 :5 ! normal values sl[ly reass]t$ !mselves4 ,among/ s _m v>ieties ( ^! preci\s m9]als1 x _c be o!rwise ?an t !re %\ld be important diff]5ces 9 _! v>i\s *>act]i/ics1 ?\gh = a /one to h ! slighte/ claim to be class$ z preci\s x mu/ con=m to sev]al at lea/ ( ! foll[+ requirem5ts3--,x mu/ )/& ! action ( light )\t det]ioration ( its beauty1 lu/re1 or sub/ance1 & x mu/ be ( suffici5t h>dness to reta9 its =m1 purity & lu/re "u ! actions ( w>m?1 reasonable we>1 & ! du/ :i* falls ^u x dur+ use2 x mu/ n be subject to *emical *ange1 decomposition1 dis9tegration1 or o!r alt]ation ( its sub/ance "u exposure to atmosph]ic air2 o!rwise x is useless = all practical purposes ( adornm5t or ornam5tation4 ,!re are c]ta9 o!r *>act]i/ics ( ^! curi\s m9]als :i* may be classifi$ briefly1 ?us3--,"s /ones owe _! beauty to a wond]ful play ( col\r or fire1 due to ! action ( light1 q ap>t f ! col\r ( ! /one itself1 & ( ?is s]ies ! opal may be tak5 z a type4 ,9 o!rs1 ?is spl5did play ( col\r is altoge!r abs5t1 ! col\r be+ associat$ ) ! /one itself1 9 its sub/ance1 ! *>m ly+ entirely 9 ! sup]b transp>5cy1 ! ruby be+ tak5 z an example ( ?is class ( /one4 ,o!rs1 aga91 h n only col\r1 b transp>5cy & lu/re1 z 9 ! col\r$ diamonds1 :il/ ! common] well-kn[n diamonds are extremely ri* 9 transp>5cy & lu/re1 ! play ( light alone %[+ a consid]able am\nt ( brilliancy & beauty ( col\r1 ?\gh ! /one itself is cle>4 ,/ill o!rs are opaque1 or semi-opaque1 or practically free f play ( light & f lu/re1 ow+ _! value & beauty entirely to _! ri*ness ( col\r4 ,9 all cases ! value ( ! /one _c be appreciat$ fully till ! gem is sep>at$ f its matrix & poli%$1 & 9 "s cases1 su* z 9 t ( ! diamond1 cut 9 v>i\sly %ap$ facets1 on & among/ :i* ! light rays h p[] to play2 o!r /ones1 su* z ! opal1 turquoise & ! l1 are cut or gr\nd 9 flat1 dome-%ap$1 or o!r =m1 & !n m]ely poli%$4 ,x frequ5tly happ5s t only a small portion ( ev5 a l>ge /one is ( supreme value or purity1 ! cutt] (t5 reta9+ z 8 p]quisite ! small] pieces & wa/e4 ,^!1 if too small = sett+1 are gr\nd into p[d] & us$ to cut & poli% o!r /ones4 ,broadly speak+1 ! greate/ claim :i* a /one c possess 9 ord] to be class$ z preci\s is its r>ity4 ,to ?is may be add$ public op9ion1 :i* is l$ = bett] or worse by ! fa%ion ( ! mom5t4 ,= if ! comp>atively common ame?y/ %\ld *ance to be made extraord9>ily conspicu\s by "s society lead]1 x w\ld at once /ep f its humbl] position z semi-preci\s1 & rise to ! nobl] classification ( a truly preci\s /one1 by reason ( ! dem& creat$ = x1 :i* w\ld1 9 all probability1 absorb ! available /ock to r>ity2 & ?is despite ! m entranc+ beauty ( ! n[ r>] /ones4 ,! /udy ( ?is section ( m9]alogy is "o ( int5se int]e/1 & by und]/&+ ! nature1 environm5t1 *emical composition & ! prop]ties ( ! /ones1 possibility ( fraud is altoge!r preclud$1 & !re is induc$ 9 ! m9d--ev5 ( ^? ) :om ! /udy ( preci\s /ones has no "p comm]cially--an intellig5t int]e/ 9 ! sight or association ( :at might o!rwise excite no m ?an a m]e glance ( admiration or curiosity4 ,!re is sc>cely any =m ( matt]1 be x liquid1 solid1 or gase\s1 b has yield$ or is n[ yield+ up its secrets ) m or less fre$om to ! sci5ti/4 ,by 8 me?od ( syn!sis 7:i* is ! sci5tific "n = putt+ sub/ances toge!r 9 ord] to =m new comp\nds out ( _! union7 or ( analysis 7! decompos+ ( bodies s z to divide or sep>ate !m into sub/ances ( less complexity71 p>ticul>ly ! latt]1 he sl[ly & surely breaks d[n ! sub/ances und]go+ exam9ation into _! v>i\s con/itu5ts1 r$uc+ ^! /ill fur!r till no m r$uction is possible1 & he arrives at _! elem5ts4 ,f _! behavi\r dur+ ! _m & v>i$ processes ?r\gh :i* !y h pass$ he f9ds out1 ) un]r+ accuracy1 ! exact proportions ( _! composition1 &1 9 _m cases1 ! cause ( _! orig94 ,x may be ?\ght t1 kn[+ all ?is1 x is /range t man does n himself manufacture ^! r>e gems1 su* z ! diamond1 b s f> he has only succe$$ 9 mak+ a few ( microscopic size1 altoge!r useless except z sci5tific curiosities4 ,! mann] 9 :i* ^! m9ute gems & spuri\s /ones are manufactur$1 & ! me?ods by :i* !y may readily be di/+ui%$ f real1 w be dealt ) 9 due c\rse4 ,! natural /ones repres5t ! sl[ *emical action ( wat]1 decay1 & association )1 or ne>1 o!r *emical sub/ances or elem5ts1 comb9$ ) ! action ( millions ( ye>s ( "t1 & ! unceas+ enorm\s pressure dur+ t "t ( ?\s&s1 p]haps millions1 ( tons ( e>?1 rock1 & ! l1 subject$1 = a c]ta9 portion at lea/ ( t p]iod1 to extremes ( heat or cold1 all ( :i* det]m9e ! nature ( ! gem4 ,s t only 9 ! e>? itself1 "u /rictly natural conditions1 c ^! r>e sub/ances be f\nd at all 9 any workable size2 !re=e !y mu/ be s\ght aft] assidu\sly1 ) m or less speculative risk4 ,,*apt] ,,ii4 ,,! ,,orig9 ,,( ,,preci\s ,,/ones4 ,?\gh ! orig91 =mation1 composition1 *>act]i/ics & te/s ( ea* /one w be exam9$ 9 detail :5 deal+ ) ! /ones s]iatim1 x is necess>y to enquire into ^? p>ticul>s ( orig9 :i* are common to all1 9 ord] ?or\ghly to und]/& :y !y diff] f o!r non-metallic & metallic m9]als4 ,at ! v comm5cem5t we are fac$ ) a subject on :i* m9]alogi/s & geologi/s are by no means 9 full agreem5t1 & !re seems j gr\nd = consid]able div]g5ce ( op9ion1 accord+ to ! l9e ( argum5t tak54 ,x is a mo/ rem>kable fact t1 preci\s z are c]ta9 /ones1 !y d n 7) a few exceptions7 conta9 any ( ! r>] metals1 su* z plat9um1 gold1 etc41 or any ( _! comp\nds1 b are compos$ entirely ( ! common elem5ts & _! d]ivatives1 especially ( ^? elem5ts conta9$ 9 ! upp] cru/ ( ! e>?1 & ?is not)/&+ ! fact t gems are (t5 f\nd deep d[n 9 ! e>?4 ,?is is v significant1 & po9ts to ! conclusion t ^! /ones 7 =m$ by ! sl[ p]colation ( wat] f ! surface ?r\gh ! deep] p>ts ( ! e>?1 c>ry+ ) x1 9 solution or susp5sion1 ! *emical con/itu5ts ( ! e>?'s upp] cru/2 "t & long-cont9u$ pressure1 comb9$ ) heat or cold1 or p]haps bo? 9 turn1 do+ ! re/1 z already m5tion$4 ,! moi/ure fall+ 9 dew & ra9 becomes acidulat$ ) c>bonic acid1 ,,co#b 7c>bon dioxide71 f ! combu/ion & decay ( organic matt]1 vegetation1 & o!r s\rces1 & ?is moi/ure is capable ( dissolv+ c]ta9 calc>e\s sub/ances1 :i* x takes deep into ! e>?1 till ! "t comes :5 x ent]s p]haps a division-plane 9 "s rock1 or "s su* cavity1 & is unable to get away4 ,! holl[ becomes fill$ ) wat]1 :i* is sl[ly m & m *>g$ ) ! salts br\ght d[n1 till saturat$2 !n sup]-saturat$1 s t ! salts become precipitat$1 or p]haps cry/allis$ out1 maybe by ! pres5ce ( m or o!r salts1 or by a *ange 9 temp]ature4 ,^! cry/als !n become pack$ h>d by fur!r supplies & pressure1 till ev5tually1 aft] ! lapse ( ages1 a natural gem is f\nd1 exactly fill+ ! cavity1 & is a preci\s f9d 9 _m cases4 ,if n[ we try to f9d its analogy 9 *emi/ry1 & = a mom5t consid] ! curi\s behavi\r ( "s well-kn[n salts1 "u diff]5t conditions ( temp]ature1 :at is tak+ place und]gr\nd ceases to be my/]i\s & becomes readily intelligible4 ,p]haps ! be/ salt = ! purpose1 & "o easy to obta9 = exp]im5t1 is ! sulphate ( sodium--kn[n also z ,glaub]'s ,salt4 ,x is 9 l>ge1 col\rless prisms1 :i* may soon be dissolv$ 9 ab\t ?ree p>ts ( wat]1 s long z ! wat] does n exce$ #fj deg4 ,f41 & at ?is temp]ature a sup]-saturat$ solution may easily be made4 ,b if ! wat] is heat$ ! salt !n becomes m & m insoluble z ! temp]ature increases1 till x is completely insoluble4 ,if a sup]-saturat$ solution ( ?is ,glaub]'s ,salt is made 9 a glass1 at ord9>y atmosph]ic temp]ature1 & into ?is cold solution1 )\t heat+1 is dropp$ a small cry/al ( ! same salt1 !re w be caus$ a rise 9 temp]ature1 & ! :ole w !n cry/allise out q sudd5ly2 ! wat] w be absorb$1 & ! :ole w solidify into a mass :i* exactly fits ! inn] cont\r ( ! vessel4 ,we h n[ =m$ :at might be a preci\s /one1 & no d\bt w\ld be1 if cont9u\s pressure c\ld be appli$ to x = p]haps a few ?\s& ye>s2 at any rate1 ! =mation ( a natural jewel is n greatly diff]5t1 & aft] be+ subject$ = a p]iod1 ext5d+ to ages1 to ! wa%+s ( moi/ure1 ! contact ( its conta9+ b$ 7its lat] matrix71 ! action ( ! *anges 9 ! temp]ature ( ! e>? 9 its vic9ity1 x em]ges by volcanic eruption1 e>?quake1 l&slip & ! l1 or is discov]$ z a r>e & valuable specim5 ( "s simple comp\nd ( e>?-cru/ & wat]1 z simple z ,glaub]'s ,salt1 or z ! pure cry/alliz$ c>bon4 ,x is also curi\s to note t 9 "s cases ! /ones h n be5 caus$ by aque\s deposit 9 an already exi/+ holl[1 b ! aque\s infusion has act$ on a portion ( ! rock on :i* x re/$1 absorb+ ! rock1 &1 z x 71 replac+ x by its own sub/ance4 ,?is is evid5c$ 9 cases :]e gems h be5 f\nd encru/$ on _! matrix1 :i* latt] 0 be+ sl[ly trans=m$ to ! "* ( ! jewel encru/$1 or scabb$ on x4 ,! "* ( ! matrix is also 9 a great measure ! cause ( ! v>iety ( ! /one1 = x is obvi\s t ! same salt-*>g$ aque\s solution :i* und]goes *ange 9 & on iron/one w\ld result 9 an entirely diff]5t product f t re/+ on or emb$d$ 9 silica4 ,foll[+ out ! explanation ( ! aque\s solution1 9 :i* ! e>?-cru/ con/itu5ts are secret$1 we f9d t ! r>] & m preci\s metals d n g5]ally ent] into ! composition ( preci\s /ones--:i* fact may advis$ly be repeat$4 ,x is1 ( c\rse1 to be expect$ t b]yllium w be f\nd 9 ! em]ald1 s9ce x is "u ! species b]yl1 & zirconium 9 zircon2 b su* in/ances are ! exception1 & we may well wond] at ! actions ( ! inf9ite p[]s ( nature1 :5 we reflect t ! r>e/1 co/lie/ & mo/ beautiful ( all preci\s /ones are ! simple/ 9 _! con/itu5ts4 ,?us we f9d ! diamond /&+ unique among/ all gems 9 be+ compos$ ( "o elem5t only--c>bon--be+ pure cry/allis$ c>bon2 a diff]5t =m f graphite1 x is true1 b1 nev]!less1 pure c>bon & no?+ else4 ,!re=e1 f its *emical1 z well z f its comm]cial aspect1 ! diamond /&s alone z ! mo/ important ( gems4 ,! next 9 simplicity1 :il/ be+ ! mo/ co/ly ( all1 is ! ruby1 & ) ?is may be class$ ! blue sapphire1 see+ t _! *emical con/itu5ts are exactly ! same1 ! diff]5ce be+ "o ( col\r only4 ,^! h two elem5ts1 oxyg5 & alum9ium1 :i* important con/itu5ts appe> also 9 o!r /ones1 b ?is example is suffici5t to prove _! simplicity ( orig94 ,ano!r unique /one is ! turquoise1 9 t x is ! only r>e gem ess5tially conta9+ a great proportion ( wat]1 :i* r5d]s x easily liable to de/ruction1 z we %all see lat]4 ,x is a comb9ation ( alum9a1 wat]1 & phosphoric acid1 & is also unique 9 be+ ! only kn[n valuable /one conta9+ a phosphate4 ,turn+ to ! silica s]ies1 we aga9 f9d a numb] ( gems ) two elem5ts only1 silica--an important con/itu5t ( ! e>?'s cru/--& oxyg5--an important con/itu5t ( atmosph]ic air4 ,9 ?is gr\p may be m5tion$ ! opal1 ame?y/1 agate1 rock-cry/al1 & ! l1 z ! be/ kn[n examples1 :il/ oxyg5 appe>s also mo/ly 9 ! =m ( oxides1 9 *rysob]yl1 sp9el1 & ! l4 ,?is silica gr\p is extremely int]e/+1 = 9 x1 ) ! exception ( ! t\rmal9e & a few o!rs1 ! composition ( ! gems is v simple1 & we f9d 9 ?is gr\p su* /ones z ! *rysolite1 sev]al v>ieties ( topaz1 ! g>net1 em]ald1 etc41 etc4 ,mala*ite & simil> /ones are m ornam5tal ?an preci\s1 ?\gh !y come 9 ! category ( preci\s /ones4 ,^! are ! c>bonate s]ies1 conta9+ mu* c>bonic acid1 &1 z may be expect$1 a consid]able proportion ( wat] 9 _! composition1 :i* wat] c1 ( c\rse1 be dispell$ by ! application ( heat1 b to ! de/ruction ( ! /one4 ,f all ?is w be se5 h[ /rong is ! !ory ( aque\s p]colation1 =1 giv5 "t & pressure1 wat] *>g$ ) e>?-cru/ con/itu5ts appe>s to be ! orig9 ( ! =mation ( all preci\s /ones2 & all ! preci\s /ones kn[n h1 :5 analys$1 be5 f\nd to be almo/ exclusively compos$ ( upp]-e>?-cru/ con/itu5ts2 ! o!r comp\nds :i* c]ta9 /ones conta9 may1 9 all cases1 be trac$ to _! matrix1 or to _! geological or m9]alogical situation4 ,9 contradi/9ction to ?is1 ! ess5tially und]gr\nd liquids1 ) "t & pressure1 =m metallic m9]als & m9]alise ! rocks1 in/ead ( =m+ gems4 ,?us we see t 9 a diff]5t class ( m9]als--comp\nds ( metals ) ! sulphates1 su* z sulphuric acid & comp\nds2 also ^? conta9+ ! metallic sulphides2 9 cases :]e ! metallif]\s ores or ! metallic elem5ts ent] into composition ) ! halog5s--brom9e1 *lor9e1 fluor9e1 & iod9e--9 all ^!1 preci\s /ones are comp>atively common1 b ! /ones ( ^! gr\ps are inv>iably ^? us$ = decorative or ornam5tal purposes1 & true gems are entirely abs5t4 ,x w\ld !re=e appe> t ?\gh metallic m9]als1 z already m5tion$1 are =m$ by ! action ( ess5tially und]gr\nd *emically-*>g$ wat]--comb9$ ) ages ( "t & long-cont9u$ pressure1 rocks & e>? be+ trans=m$ into metallif]\s ores by ! same means--preci\s /ones 7or t portion ( !m rank+ z jewels or gems7 mu/ on ! contr>y be :olly1 or almo/ :olly1 compos$ ( upp]-e>?-cru/ mat]ials1 c>ri$ deep d[n by wat]1 & subject$ to ! action ( ! same "t & pressure2 ! simpl] ! comp\nd1 ! m p]fect & important ! result1 z se5 9 ! diamond1 ! ruby1 & ! l4 ,,*apt] ,,iii4 ,,physical ,,prop]ties4 ,a--,,cry/all9e ,,/ructure4 ,be=e proce$+ to ! /udy ( preci\s /ones z individual gems1 c]ta9 physical prop]ties common to all mu/ be discuss$1 9 ord] to br+ ! gems into sep>ate classes1 n only because ( "s *emical uni=mity1 b also because ( ! unity :i* exi/s betwe5 _! physical =mation & prop]ties4 ,! fir/ consid]ation1 !re=e1 may advis$ly be t ( _! cry/als1 s9ce _! cry/all9e /ructure =ms a ready means = ! classification ( /ones1 & inde$ = t ( a multitud9\s v>iety ( sub/ances4 ,x is "o ( ! _m m>vell\s ph5om5a ( nature t m9]al1 z well z _m vegetable & animal sub/ances1 on ent]+ into a /ate ( solidity1 take ^u !mselves a def9ite =m call$ a cry/al4 ,^! cry/als build !mselves r\nd an axis or axes ) wond]ful regul>ity1 & x has be5 f\nd1 speak+ broadly1 t ! same sub/ance gives ! same cry/al1 no matt] h[ its "* may be alt]$ by col\r or o!r means4 ,ev5 :5 mix$ ) o!r cry/allisable sub/ances1 ! result+ cry/als may p>take ( ! two v>ieties & become a sort ( composite1 yet to ! physici/ !y are read l an op5 book1 & :5 sep>at$ by analysis !y at once rev]t to _! orig9al =m4 ,on ?is prop]ty ! analy/ dep5ds l>gely = 8 results1 = 9 su* matt]s z food adult]ation1 etc41 ! microscope un]r+ly reveals impurities by means ( ! cry/als alone1 ap>t f o!r evid5ces4 ,x is mo/ curi\s1 too1 to note t no matt] h[ l>ge a cry/al may be1 :5 r$uc$ ev5 to small size x w be f\nd t ! cry/als are /ill ( ! same %ape4 ,if ?is process is tak5 /ill fur!r1 & ! sub/ance is gr\nd to ! f9e/ impalpable p[d]1 z f9e z float+ du/1 :5 plac$ "u ! microscope ea* speck1 ?\gh p]haps invisible to ! nak$ eye1 w be se5 a p]fect cry/al1 ( ! id5tical %ape z t f :i* x came1 "o s l>ge maybe t its planes & angles might h be5 measur$ & def9$ by rule & compass4 ,?is %[s h[ impossible x is to alt] ! %ape ( a cry/al4 ,we may dissolve x1 p\r ! solution into any %ap$ vessel or m\ld we desire1 recry/allise x & obta9 a solid sph]e1 triangle1 squ>e1 or any o!r =m2 x is also possible1 9 _m cases1 to squeeze ! cry/al by pressure into a tablet1 or any =m we *oose1 b 9 ea* case we h m]ely alt]$ ! arrangem5t ( ! cry/als1 s z to produce a diff]5tly %ap$ mass1 ! cry/als !mselves rema9+ individually z be=e4 ,su* c be said to be "o ( ! laws ( cry/als1 & z x is f\nd t e sub/ance has its own =m ( cry/al1 a sci5ce1 or bran* ( m9]alogy1 has aris51 call$ cry/allography1 & out ( ! conglom]ation ( confus$ =ms !re h be5 evolv$ c]ta9 rules ( comp>ison by :i* all kn[n cry/als may be class$ 9 c]ta9 gr\ps4 ,?is is n s labori\s a matt] z w\ld appe>1 = if we take a sub/ance :i* cry/allises 9 a cube we f9d x is possible to draw n9e symmetrical planes1 ^! be+ call$ planes ( symmetry1 ! int]sections ( "o or m ( :i* planes be+ call$ axes ( symmetry4 ,s t 9 ! n9e planes ( symmetry ( ! cube we get ?ree axes1 ea* runn+ ?r\gh to ! opposite side ( ! cube4 ,"o w be ?r\gh ! c5tre ( a face to ! opposite face2 a second w be ?r\gh ! c5tre ( "o edge diagonally2 ! ?ird w be f\nd 9 a l9e runn+ diagonally f "o po9t to its opposite4 ,on turn+ ! cube on ^! ?ree axes--z1 = example1 a long ne$le runn+ ?r\gh a cube ( soap--we %all f9d t f\r ( ! six id5tical faces ( ! cube are expos$ to view dur+ ea* revolution ( ! cube on ! ne$le or axis4 ,^! faces are n necess>ily1 or always1 planes1 or flat1 /rictly speak+1 b are (t5 m or less curv$1 accord+ to ! %ape ( ! cry/al1 tak+ c]ta9 *>act]i/ic =ms1 su* z ! squ>e1 v>i\s =ms ( triangles1 ! rectangle1 etc41 & ?\gh ! cry/als may be a comb9ation ( sev]al =ms1 all ! faces ( any p>ticul> =m are simil>4 ,all ! cry/als at pres5t kn[n exhibit diff]5ces 9 _! planes1 axes & l9es ( symmetry1 & on c>eful comp>ison _m ( !m are f\nd to h "s features 9 common2 s t :5 !y are sort$ out x is se5 t !y are capable ( be+ classifi$ into ?irty-?ree gr\ps4 ,_m ( ^! gr\ps are analog\s1 s t on analys+ !m /ill fur!r we f9d t all ! kn[n cry/als may be class$ 9 six sep>ate sy/ems accord+ to _! planes ( symmetry1 & all /ones ( ! same class1 no matt] :at _! v>iety or complexity may be1 %[ =ms ( ! same gr\p4 ,beg9n+ ) ! highe/1 we h--7#a7 ! cubic sy/em1 ) n9e planes ( symmetry2 7#b7 ! hexagonal1 ) sev5 planes2 7#c7 ! tetragonal1 ) five planes2 7#d7 ! rhombic1 ) ?ree planes2 7#e7 ! monocl9ic1 ) "o plane2 7#f7 ! tricl9ic1 ) no plane ( symmetry at all4 ,9 ! fir/1 ! cubic--call$ also ! isometric1 monometric1 or regul>--!re are1 z we h se51 ?ree axes1 all at "r angles1 all ( !m be+ equal4 ,! second1 ! hexagonal sy/em--call$ also ! rhomboh$ral--is diff]5t f ! o!rs 9 hav+ f\r axes1 ?ree ( !m equal & 9 "o plane & all at #abj deg4 to ea* o!r2 ! f\r? axis is n always equal to ^! ?ree4 ,x may be1 & (t5 is1 long] or %ort]4 ,x passes ?r\gh ! int]sect+ po9t ( ! ?ree o!rs1 & is p]p5dicul> or at "r angles to !m4 ,! ?ird ( ! six sy/ems enum]at$ above1 ! tetragonal--or ! quadratic1 squ>e prismatic1 dimetric1 or pyramidal--sy/em has ?ree axes l ! cubic1 b1 9 ?is case1 ?\gh !y are all at "r angles1 two only ( !m are equal1 ! ?ird1 consequ5tly1 unequal4 ,! v]tical or pr9cipal axis is (t5 mu* long] or %ort] 9 ?is gr\p1 b ! o!r two are always equal & lie 9 ! horizontal plane1 at "r angles to ea* o!r1 & at "r angles to ! v]tical axis4 ,! f\r? sy/em1 ! rhombic--or or?orhombic1 or prismatic1 or trimetric--has1 l ! tetragonal1 ?ree axes2 b 9 ?is case1 none ( !m are equal1 ?\gh ! two lat]al axes are at "r angles to ea* o!r1 & to ! v]tical axis1 :i* may v>y 9 l5g?1 m s ev5 ?an ! o!r two4 ,! fif?1 ! monocl9ic--or cl9orhombic1 monosymmetric1 or oblique--sy/em1 has also ?ree axes1 all ( !m unequal4 ,! two lat]al axes are at "r angles to ea* o!r1 b ! pr9cipal or v]tical axis1 :i* passes ?r\gh ! po9t ( int]section ( ! two lat]al axes1 is only at "r angles to "o ( !m4 ,9 ! six? & la/ sy/em1 ! tricl9ic--or anor?ic1 or asymmetric--! axes are aga9 ?ree1 b 9 ?is case1 none ( !m are equal & none at "r angles4 ,x is difficult to expla9 ^! v>i\s sy/ems )\t draw+s1 & ! =ego+ may seem unnecess>ily te*nical4 ,x is1 h[ev]1 ess5tial t ^! p>ticul>s %\ld be cle>ly /at$ 9 ord] ?or\ghly to und]/& h[ /ones1 especially uncut /ones1 are classifi$4 ,^! v>i\s gr\ps mu/ also be ref]r$ to :5 deal+ ) ! action ( light & o!r matt]s1 = 9 "o or o!r ( !m mo/ /ones are plac$1 not)/&+ great diff]5ces 9 hue & "*2 ?us all /ones exhibit+ ! same cry/all9e /ructure z ! diamond are plac$ 9 ! same gr\p4 ,fur!r1 :5 ! me?ods ( te/+ come to be dealt )1 x w be se5 t ^! p>ticul>s ( gr\p+ =m a c]ta9 means ( te/+ /ones & ( di/+ui%+ spuri\s f real4 ,= if a /one is (f]$ z a real gem 7! true /one be+ kn[n to lie 9 ! highe/ or cubic sy/em71 x foll[s t %\ld exam9ation prove ! /one to be 9 ! six? sy/em1 !n1 no matt] h[ col\r$ or cut1 no matt] h[ p]fect ! imitation1 ! te/ ( its cry/all9e /ructure /amps x readily z false beyond all %ad[ ( d\bt--= z we h se51 no human means h z yet be5 =?com+ by :i* ! cry/als c be *ang$ 9 =m1 only 9 arrangem5t1 = a diamond cry/al is a diamond cry/al1 be x 9 a l>ge mass1 l ! brighte/ & l>ge/ gem s f> discov]$--! great ,cull9an diamond--or ! t9ie/ gra9 ( microscopic diamond-du/1 & s on ) all preci\s /ones4 ,s t 9 future ref]5ces1 to avoid repetition1 ^! gr\ps w be ref]r$ to z gr\p #a1 #b1 & s on1 z detail$ "h4 ,,*apt] ,,iv4 ,,physical ,,prop]ties4 ,b--,,cleavage4 ,by cleavage is meant ! mann] 9 :i* m9]als sep>ate or split (f ) regul>ity4 ,! diff]5ce betwe5 a break or fracture & a cleave1 is t ! =m] may be any:]e ?r\gh\t ! sub/ance ( ! brok5 body1 ) an extremely remote *ance ( ano!r fracture be+ id5tical 9 =m1 :]eas 9 ! latt]1 :5 a body is cleav$1 ! fractur$ "p is m readily sev]$1 & usually takes a simil> if n an actually id5tical =m 9 ! divid$ surface ( ea* piece sev]$4 ,?us we f9d a piece ( wood may be brok5 or *opp$ :5 fractur$ across ! gra91 no two fractur$ edges be+ alike2 b1 /rictly speak+1 we only cleave wood :5 we split x ) ! gra91 or1 9 sci5tific language1 along ! l9e ( cleavage1 & !n we f9d _m pieces ) _! divid$ surfaces id5tical4 ,s t :5 wood is brok51 or *opp$1 we obta9 pieces ( any wid? or ?ickness1 ) no mann] ( regul>ity ( fracture1 b :5 cleav$1 we obta9 /rips :i* are (t5 p]fectly p>allel1 t is1 ( equal ?ickness ?r\gh\t _! :ole l5g?1 & ( su* uni=mity ( surface t x is difficult or ev5 impossible to di/+ui% "o /rip f ano!r4 ,advantage is tak5 ( ^! l9es ( cleavage to procure long & extremely ?9 ev5 /rips f trees ( ! will[ v>iety = su* trades z basket-mak+4 ,! same effect is se5 9 h\se-coal1 :i* may easily be split ! way ( ! gra9 7on ! l9es ( cleavage71 b is mu* m difficult & requires great] =ce to break across ! gra94 ,rocks also %[ di/9ct l9es ( cleavage1 & are m readily split "o way ?an ano!r1 ! l9e ( cleavage or /ratum ( break be+ at any angle & n necess>ily p>allel to its b$4 ,a /rik+ example ( ?is is se5 9 slate1 :i* may be split 9 plates1 or lam9ae1 ) great facility1 ?\gh ?is prop]ty is ! result ( ! pressure to :i* ! rock has be5 = ages subject$1 :i* has caus$ a *ange 9 ! molecules1 r ?an by cleavage z ! t]m is /rictly und]/ood1 & z exi/+ 9 m9]als4 ,mica is also ano!r example ( lam9at$ cleavage1 = giv5 c>e1 & a ?91 f9e knife to divide ! plates1 ?is m9]al may be cleav$ to su* rem>kably ?9 %eets z to be unable to su/a9 ! mo/ delicate t\* )\t %att]+4 ,^! are well-kn[n examples ( simple cleavage1 9 "o def9ite direction1 ?\gh 9 _m in/ances !re are sev]al =ms & directions ( cleavage1 b ev5 9 ^! !re is g5]ally "o "p or l9e 9 & on :i* cleavage w take place mu* m readily ?an on ! o!rs1 ^! planes or l9es also %[+ diff]5t prop]ties & angul> *>act]s1 :i*1 no matt] h[ mu* fractur$1 always rema9 ! same4 ,x is ?is cleavage :i* causes a cry/al to reproduce itself exactly1 z expla9$ 9 ! la/ *apt]1 %[+ its p>5t =m1 %ape & *>act]i/ics ) microscopic p]fection1 b m & m 9 m9iature z its size is r$uc$4 ,?is may cle>ly be se5 by tak+ a v small quantity ( su* a sub/ance z *lorate ( pota%4 ,if a cry/al ( ?is is exam9$ "u a magnify+ glass till its cry/all9e =m & /ructure are famili>1 & x is !n plac$ 9 a te/-tube & g5tly heat$1 cleavage w at once be evid5t4 ,) a little crackl+1 ! *lorate splits itself into _m cry/als along its *ief l9es ( cleavage 7call$ ! cleavage planes71 e "o ( :i* cry/als %[+ "u ! microscope ! id5tical =m & *>act]i/ics ( ! l>g] cry/al f :i* x came4 ,! cleavage ( m9]als mu/1 !re=e1 be consid]$ z a "p ( _! cry/all9e /ructure1 s9ce ?is is caus$ by cleavage1 s t bo? cleavage & cry/all9e /ructure %\ld be consid]$ toge!r4 ,?us we see t giv5 an un*angeable cry/al ) cleavage planes evid5t1 x is possible easily to reproduce ! same =m ov] & ov] aga9 by splitt+1 :]eas by simply break+1 ! =m ( ! cry/al w\ld be lo/2 j z a rhomb ( ,icel& sp> might be sawn or brok5 across ! middle & its =m lo/1 al?\gh ?is w\ld really be m app>5t ?an real1 s9ce x w\ld be an alt]ation 9 ! mass & n 9 ! %ape ( ea* individual cry/al4 ,& giv5 fur!r cleavage1 by "t or a sudd5 break+ d[n1 ev5 ! mass1 z mass1 w\ld ev5tually become split into small] b p]fect rhombs4 ,mu* skill is1 !re=e1 requir$ 9 cutt+ & fa%ion+ a preci\s /one1 o!rwise ! gem may be ru9$ at ! onset1 = x w only divide along its l9es ( cleavage1 & any mi/ake 9 decid+ ^u ^!1 w\ld break1 n split ! /one1 & de/roy ! beauty ( its cry/all9e /ructure4 ,an example ( ?is 0 specially se5 9 ! great ,cull9an diamond1 ! splitt+ ( :i* 0 p]haps ! mo/ ?rill+ mom5t 9 ! hi/ory ( preci\s /ones4,a ,! value ( ! enorm\s cry/al 0 almo/ beyond computation1 b x _h a flaw 9 ! c5tre1 & 9 ord] to cut out ?is flaw x 0 necess>y to divide ! /one into two pieces4 ,! planes ( cleavage 7 work$ out1 ! diamond 0 sawn a little1 :5 ! op]ator1 ackn[l$g$ to be ! greate/ liv+ exp]t1 ins]t$ a knife 9 ! saw-m>k1 & ) ! second bl[ ( a /eel rod1 ! m>vell\s /one p>t$ precisely z int5d$1 cutt+ ! flaw exactly 9 two1 leav+ half ( x on ! outside ( ea* divid$ portion4 ,! slighte/ miscalculation w\ld h meant enorm\s loss1 if n ru91 to ! /one1 b ! greate/ feat ! _w has ev] kn[n 9 ! splitt+ ( a priceless diamond 0 accompli%$ successfully by ?is skilful exp]t 9 an ,am/]dam workroom 9 ,febru>y1 #aijh4 ,"s idea ( ! risk involv$ may be ga!r$ f ! fact t ?is /one1 ! l>ge/ ev] discov]$1 9 ! r\gh weigh$ ne>ly #c1bed c>ats1 its value be+ almo/ any?+ "o c>$ to /ate--incalculable4 ,footnote ,a3 ,! hamm] & knife us$ 9 cutt+ ! diamond1 ! two l>ge/ pieces ( :i* are n[ call$ ,! ,/>s ( ,africa1 toge!r ) a model ( ! great uncut /one1 are 9 ! ,t[] ( ,london among/ ! ,regalia4 ,^! cleavage planes help consid]ably 9 ! br++ ( ! /one to %ape1 = 9 a broad s5se1 a f9i%$ cut /one may be said to be 9 ! =m 9 :i* its cleavages br+ x4 ,p>ticul>ly is ?is se5 9 ! diamond brilliant1 :i* pla9ly evid5ces ! f\r cleavage planes4 ,^! cleavage planes & _! numb] are a simple means ( id5tification ( preci\s /ones1 ?\gh ^? possess+ di/9ct & ready cleavages are extremely liable to />t or split on ^! planes by extremes ( heat & cold1 accid5tal bl[s1 sudd5 %ocks & ! l4 ,9 /ones possess+ c]ta9 cry/all9e /ructure1 ! cleavage planes are ! readie/1 (t5 ! only1 means ( id5tification1 especially :5 ! /ones are *emically col\r$ to imitate a m valuable /one4 ,9 su* cases ! cleavage ( "o /one is (t5 ( p>am\nt importance 9 te/+ ! cleavage ( ano!r1 z is se5 9 ! p]fection ( ! cleavage planes ( calcite1 :i* is us$ 9 ! pol>iscope4 ,x sometimes happ5s1 h[ev]1 t false conditions arise1 su* z 9 sub/ances :i* are ( no =m or %ape1 & are 9 all respects & directions )\t regul> /ructure & %[ no cry/allisation ev5 9 ! m9ute/ p>ticles2 ^! are call$ amorph\s4 ,su* a condition sometimes ent]s :olly or p>tially into ! cry/all9e /ructure1 & ! m9]al loses its true =m1 possess+ in/ead ! =m ( cry/als1 b )\t a cry/all9e /ructure4 ,x is !n call$ a pseudomorph1 :i* is a t]m appli$ to any m9]al :i*1 in/ead ( hav+ ! =m x %\ld possess1 %[s ! =m ( some?+ :i* has alt]$ its /ructure completely1 & !n disappe>$4 ,= in/ance3 v (t51 9 a c]ta9 cavity1 fluorsp> has exi/$ orig9ally1 b1 ?r\gh "s *emical means1 has be5 sl[ly *ang$ to qu>tz1 s t1 z cry/als _c be *ang$ 9 %ape1 we f9d qu>tz exi/+--und5iably qu>tz--yet possess+ ! cry/als ( fluorsp>2 !re=e ! qu>tz becomes a pseudomorph1 ! condition be+ an example ( :at is t]m$ pseudomorphism4 ,! actual cause ( ?is curi\s *emical *ange or sub/itution is n kn[n ) c]ta9ty1 b x is int]e/+ to note ! conditions 9 :i* su* *anges d occur4 ,x is f\nd t 9 "s cases1 ! matrix ( a c]ta9 %ap$ cry/al may1 aft] ! cry/al is dissolv$ or tak5 away1 become fill$ by "s o!r & =eign sub/ance1 p]haps 9 liquid =m2 or a cry/all9e sub/ance may become coat$ or inve/$ by ano!r =eign sub/ance1 :i* ?us takes its %ape2 or actual *emical *ange takes place by means ( an incom+ sub/ance :i* sl[ly alt]s ! orig9al sub/ance1 s t ev5tually ea* is false & bo? become pseudomorphs4 ,?is curi\s *ange (t5 takes place ) preci\s /ones1 z well z ) o!r m9]als1 & to su* an ext5t t x sometimes becomes difficult to say :at ! /one ought really to be call$4 ,pseudomorphs are1 h[ev]1 comp>atively easy ( isolation & detection1 be+ m or less r\nd$ 9 _! cry/all9e =m1 in/ead ( hav+ %>p1 well-def9$ angles & edges2 _! surfaces also are n good4 ,^! /ones are ( little value1 except 9 ! specially curi\s examples1 :5 !y become r>e m by reason ( _! curiosity ?an by _! utility z gems4 ,"s also %[ cleavage planes ( two or m sy/ems1 & o!rs %[ a cry/all9e /ructure compris$ ( sev]al sy/ems4 ,?us calcsp> is 9 ! #bnd1 or hexagonal1 :il/ aragonite is 9 ! #d?1 ! rhombic1 sy/em1 yet bo? are ! same sub/ance1 viz43--c>bonate ( lime4 ,su* a condition is call$ dimorphism2 ^? m9]als :i* cry/allise 9 ?ree sy/ems are said to be trimorph\s4 ,^? 9 a numb] ( sy/ems are polymorph\s1 & ( ^! sulphur may be tak5 z an example1 s9ce x possesses ?irty or m modifications ( its cry/all9e /ructure1 ?\gh "s au?orities elim9ate ne>ly all ^!1 &1 s9ce x is mo/ frequ5tly 9 ei!r ! #d? 7rhombic7 or ! #e? 7monocl9ic7 sy/ems1 consid] x z an example ( dimorphism1 r ?an polymorphism4 ,^! v>ieties ( cleavage affect ! "*1 beauty & usefulness ( ! /one to a rem>kable ext5t1 & at ! same "t =m a means ( ready & c]ta9 id5tification & classification4 ,,*apt] ,v4 ,,physical ,,prop]ties4 ,c--,,light4 ,probably ! mo/ important ( ! _m important physical prop]ties possess$ by preci\s /ones are ^? ( light & its effects1 = to ^! all kn[n gems owe _! beauty1 if n actual fasc9ation4 ,:5 light /rikes a cut or poli%$ /one1 "o or m ( ! foll[+ effects are obs]v$3--x may be transmitt$ ?r\gh ! /one1 diaphaneity1 z x is call$2 x may produce s+le or d\ble refraction1 or pol>isation2 if reflect$1 x may produce lu/re or col\r2 or x may produce phosphoresc5ce2 s t light may be 7#a7 transmitt$2 7#b7 reflect$2 or produce 7#c7 phosphoresc5ce4 7#a7 ,,transmission4--,9 transmitt$ light we h1 z /at$ above1 s+le or d\ble refraction1 pol>isation1 & diaphaneity4 ,to ! quality ( refraction is due "o ( ! *ief *>ms ( c]ta9 preci\s /ones4 ,x is n necess>y to expla9 "h :at refraction is1 = ev]yone w be famili> ) ! refractive prop]ty ( a light-beam :5 pass+ ?r\gh a m$ium d5s] ?an atmosph]ic air4 ,x w be q suffici5t to say t all ! rays are n equal 9 refractive p[] 9 all sub/ances1 s t ! middle ( ! spectrum is g5]ally select$ z ! mean = index+ purposes4 ,x w be se5 t ! /ones 9 ! #a/1 or cubic sy/em1 %[ s+le refraction1 :]eas ^? ( all o!r sy/ems %[ d\ble refraction2 ?us1 light1 9 pass+ ?r\gh _! sub/ance1 is deviat$1 "p ( x go+ "o way1 ! o!r portion go+ 9 ano!r direction--t is1 at a slightly diff]5t angle--s t ?is prop]ty alone w isolate readily all gems belong+ to ! #a/ sy/em4 ,a well-kn[n simple exp]im5t 9 physics %[s ?is cle>ly4 ,a m>k on a c>d or pap] is view$ ?r\gh a piece ( d\ble-refract+ sp> 7,icel& sp> or cle> calcite71 :5 ! m>k is d\bl$ & two appe>4 ,on rotat+ ?is rhomb ( sp>1 "o ( ^! m>ks is se5 to revolve r\nd ! o!r1 :i* rema9s /ation>y1 ! mov+ m>k pass+ fur!r f ! c5tre 9 places4 ,:5 ! sp> is cut & us$ 9 a c]ta9 direction1 we see b "o m>k1 & su* a position is call$ its optical axis4 ,pol>isation is :5 c]ta9 cry/als possess+ d\ble refraction h ! p[] ( *ang+ light1 giv+ x ! appe>ance ( poles :i* h diff]5t prop]ties1 & ! pol>iscope is an in/rum5t 9 :i* are plac$ pieces ( d\ble-refract+ 7,icel&7 sp>1 s t all light pass+ ?r\gh w be pol>is$4 ,s9ce only cry/als possess+ ! prop]ty ( d\ble refraction %[ pol>isation1 x foll[s t ^? ( ! #a/1 or cubic sy/em--9 :i* ! diamond /&s a prom95t example--fail to become pol>is$1 s t :5 su* a /one is plac$ 9 ! pol>iscope & rotat$1 x fails at e po9t to transmit light1 :i* a d\ble-refract+ gem all[s to pass except :5 its optical axis is plac$ 9 ! axis ( ! pol>iscope1 b ?is w be dealt ) m fully :5 ! me?ods ( te/+ ! /ones come to be consid]$4 ,diaphaneity1 or ! p[] ( transmitt+ light3--"s r f9e trade di/9ctions are drawn betwe5 ! /ones 9 ?is class1 te*nical di/9ctions made specially = purposes ( classification1 ?us3--a non-diaphan\s /one is "o :i* is q opaque1 no light ( any k9d pass+ ?r\gh its sub/ance2 a diaphan\s /one is "o :i* is altoge!r transp>5t2 semi-diaphan\s means "o n altoge!r transp>5t1 & sometimes call$ sub-transp>5t4 ,a transluc5t /one is "o 9 :i*1 ?\gh light passes ?r\gh its sub/ance1 sight is n possible ?r\gh x2 :il/ 9 a sub-transluc5t /one1 light passes ?r\gh x1 b only 9 a small degree4 ,! second physical prop]ty ( light is se5 9 ^? /ones :i* owe _! beauty or value to ,,reflection3 ?is aga9 may be dep5d5t on ,lu/re1 or ,col\r4 ,lu/re4--,?is is an important *>act]i/ic due to reflection1 & ( :i* !re are six v>ieties3--7alpha7 adamant9e 7:i* "s au?orities1 exp]ts & m]*ants subdivide z detail$ bel[72 7beta7 pe>ly2 7gamma7 silky2 7delta7 res9\s2 7epsilon7 vitre\s2 7zeta7 metallic4 ,^! may be describ$3-- 7alpha7 ,adamant9e1 or ! peculi> lu/re ( ! diamond1 s call$ f ! lu/re ( adamant9e sp>1 :i* is a =m ( corundum 7z is em]y7 ) a diamond-l lu/re1 ! h>d p[d] ( :i* is us$ 9 poli%+ diamonds4 ,x is almo/ pure anhydr\s alum9a 7,al#b,o#c7 & is1 r\ghly1 f\r times z heavy z wat]4 ,! lu/re ( ?is is ! true adamant9e1 or diamond1 brilliancy1 & ! o!r & impure divisions ( ?is p>ticul> lu/re are3 spl5d5t1 :5 objects are reflect$ p]fectly1 b ( a l[] scale ( p]fection ?an ! true adamant9e /&>d1 :i* is absolutely flawless4 ,:5 /ill l[]1 & ! reflection1 ?\gh maybe fairly good1 is some:at fuzzy1 or is confus$ or out ( focus1 x is !n m]ely %9+2 :5 /ill less di/9ct1 & no trace ( actual reflection is possible 7by :i* is meant t no object c be reproduc$ 9 any way to def9e x1 z x c\ld be def9$ 9 ! reflection f /ill wat] or ! surface ( a mirror1 ev5 ?\gh imp]fectly7 ! /one is !n said to gl9t or gli/54 ,:5 too l[ 9 ! scale ev5 to gli/51 m]ely %[+ a feeble lu/re n[ & aga9 z ! light is reflect$ f its surface 9 po9ts :i* v>y ) ! angle ( light1 ! /one is !n said to be glimm]+4 ,bel[ ?is1 ! def9itions ( lu/re d n g1 z su* /ones are said to be lu/reless4 7beta7 ,pe>ly1 z its "n implies1 is ! lu/re ( a pe>l4 7gamma7 ,silky1 possess+ ! %e5 ( silk1 h5ce its "n4 7delta7 ,res9\s1 also explanatory 9 its "n2 amb] & ! l come 9 ?is v>iety4 7epsilon7 ,vitre\s4 ,?is also expla9s itself1 be+ ( ! lu/re ( glass1 qu>tz1 etc42 "s exp]ts subdivid+ ?is = great] def9+ accuracy into ! sub-vitre\s or l[] type1 = all b p]fect specim5s4 7zeta7 ,metallic or ,sub-metallic4 ,! =m] :5 ! lu/re is p]fect z 9 gold2 ! latt] :5 ! /ones possess ! less true lu/re ( copp]4 ,col\r4--,col\r is an effect entirely dep5d5t ^u light1 = 9 ! total abs5ce ( light1 su* z 9 black d>kness1 objects are altoge!r invisible to ! normal human eye4 ,9 daylight1 also1 c]ta9 objects reflect s few vibrations ( light1 or none1 t !y appe> grey1 black1 or jet-black2 :il/ ^? :i* reflect all ! rays ( :i* light is compos$1 & 9 ! same numb] ( vibrations1 appe> :ite4 ,betwe5 ^! two extremes ( none & all we f9d a wond]ful play & v>iety ( col\r1 z "s gems all[ ! r$ rays only to pass & !re=e appe> r$2 o!rs all[ ! blue rays only & ^! appe> blue1 & s on1 ?r\gh all ! %ades1 comb9ations & v>ieties ( ! col\rs ( :i* light is compos$1 z reveal$ by ! prism4 ,b ?is is s important a matt] t x dem&s a *apt] to itself4 ,! ?ird physical prop]ty ( light1 ,,phosphoresc5ce1 is ! prop]ty possess$ by c]ta9 gems & m9]als ( becom+ phosphoresc5t on be+ rubb$1 or on hav+ _! temp]ature rais$ by ?is or o!r means4 ,x is difficult to say exactly :e!r ?is is due to ! heat1 ! friction1 or to electricity4 ,p]haps two or all ( ^! may be ! cause1 = electricity is develop$ 9 "s gems--su* z ! topaz--by heat1 & heat by electricity1 & phosphoresc5ce develop$ by bo?4 ,= example1 if we rub toge!r "s pulv]is$ fluorsp> 9 ! d>k1 or raise its temp]ature by ! direct application ( heat1 su* z f a hot or w>m iron1 or a heat$ wire1 we at once obta9 excell5t phosphoresc5ce4 ,common qu>tz1 rubb$ aga9/ a second piece ( ! same qu>tz 9 ! d>k1 becomes highly phosphoresc5t4 ,c]ta9 gems1 also1 :5 m]ely expos$ to light--sunlight = pref]5ce--!n tak5 into a d>k5$ room1 w gl[ = a %ort "t4 ,! diamond is "o ( ! be/ examples ( ?is k9d ( phosphoresc5ce1 = if expos$ to sunlight = a :ile1 !n cov]$ & rapidly tak5 into black d>kness1 x w emit a curi\s phosphoresc5t gl[ = f "o to t5 seconds2 ! pur] ! /one1 ! long]1 cle>] & bright] ! result4 ,,*apt] ,,vi4 ,,physical ,,prop]ties4 ,d--,,col\r4 ,col\r is "o ( ! mo/ wond]ful effects 9 nature4 ,x is an attribute ( light & is n a "p ( ! object :i* appe>s to be col\r$2 ?\gh all objects1 by _! *emical or physical composition1 det]m9e ! numb] & v>iety ( vibrations pass$ on or return$ to ! eye1 ?us fix+ _! own individual col\rs4 ,we h also se5 t if an equal light-beam becomes ob/ruct$ 9 its passage by "s sub/ance :i* is d5s] ?an atmosph]ic air1 x w become alt]$ 9 its direction by refraction or reflection1 & pol>is$1 ea* side or pole hav+ diff]5t prop]ties4 ,pol>is$ light _c be made aga9 to pass 9 a c]ta9 direction ?r\gh ! cry/al :i* has pol>is$ x2 nor c x aga9 be reflect$ at a p>ticul> angle2 s t 9 d\ble-refract+ cry/als1 ^! two poles1 or pol>is$ beams1 are diff]5t 9 col\r1 "s /ones be+ opaque to "o beam b n to ! o!r1 :il/ "s are opaque to bo?4 ,?is curi\s ph5om5on1 ) ?is brief1 ?\gh some:at te*nical explanation1 %[s ! cause ( _m ( ! great *>ms 9 preci\s /ones1 = :5 view$ at "o angle !y appe> ( a def9ite col\r1 :il/ at ano!r angle !y are j z decid$ 9 _! col\r1 :i* is !n entirely diff]5t2 & z ^! angles *ange z ! eye glances on v>i\s facets1 ! /one assumes a m>vell\s weal? ( ! mo/ brilliant & int5se col\r ( kaleidoscopic v>iety1 ev5 9 a /one :i* may itself be absolutely cle> or col\rless to ord9>y light4 ,su* an effect is call$ pleo*roism1 & cry/als :i* %[ v>iations 9 _! col\r :5 view$ f diff]5t angles1 or by transmitt$ light1 are call$ pleo*roic1 or pleo*romatic--f two ,greek words signify+ to col\r m4 ,to aid 9 ! exam9ation ( ?is wond]fully beautiful prop]ty possess$ by preci\s /ones1 a little in/rum5t has be5 inv5t$ call$ ! di*roscope1 its "n %[+ its ,greek d]ivation1 & mean+--to see col\r twice 7twice1 col\r1 to see74 ,x is (t5 a "p ( a pol>iscope2 frequ5tly a "p also ( ! pol>is+ atta*m5t to ! microscope1 & is s simple & +5i\s z to des]ve detail$ explanation4 ,9 a small1 brass tube is fix$ a d\ble-image prism ( calcite or ,icel& sp>1 :i* has be5 a*romatis$--t is1 cle>1 devoid ( col\r--& is !re=e capable ( transmitt+ light )\t %[+ any prismatic effect1 or all[+ ! lea/ trace ( any except ! cle> light-beam to pass ?r\gh4 ,at "o end ( ?is tube !re is a t9y squ>e hole1 ! opposite end c>ry+ a small convex l5s1 ( su* a /r5g? or focus z to %[ ! squ>e hole 9 true focus1 t is1 ) p]fectly %>p def9ition1 ev5 up to ! corn]s ( ! squ>e4 ,on look+ ?r\gh ! tube1 ! squ>e hole is duplicat$1 two squ>es be+ se54 ,! col\rs ( a gem are te/$ by ! /one be+ put 9 front ( ?is squ>e1 :5 ! two col\rs are se5 q di/9ctly4 ,n only is ?is a simple means ( judg+ col\r1 b x enables a /one to be classifi$ readily4 ,= if ! di*roscope %[s two images ( ! same col\r1 !n x may possibly be a c>buncle1 or a diamond1 z ! case may be--= s+le-refract+ /ones1 ( ! fir/ or cubic sy/em1 %[ two images ( ! same col\r4 ,b if ^! two col\rs are diff]5t1 !n x mu/ be a d\ble-refract+ /one1 & accord+ to ! p>ticul> col\rs se51 s is ! /one classifi$1 = ea* /one has its own id5tical col\r or col\rs :5 view$ ?r\gh ?is small b useful in/rum5t4 ,h[ cle> & di/9ct are ^! *anges may be view$ )\t x 9 sub/ances /rongly di*roic2 = in/ance1 if common mica is view$ 9 "o direction1 x is transp>5t z poli%$ plate-glass1 :il/ at ano!r angle1 x is totally opaque4 ,*loride ( palladium also is blood-r$ :5 view$ p>allel to its axis1 & transv]sely1 x is a rem>kably bright gre54 ,! b]yl also1 is sea-gre5 "o way & a beautiful blue ano!r2 ! yell[ *rysob]yl is br[n "o way & yell[ ) a gre5i% ca/ :5 view$ ano!r way4 ,! p9k topaz %[s rose-col\r 9 "o direction & yell[ 9 ano!r4 ,^! are p]haps ! mo/ /rik+ examples1 & are mo/ly self-evid5t to ! nak$ eye1 :il/ 9 o!r cases1 ! *anges are s delicate t ! in/rum5t mu/ be us$ to give c]ta9ty2 "s aga9 %[ *anges ( col\r z ! /one is revolv$ 9 ! di*roscope1 or ! in/rum5t revolv$ r\nd ! /one4 ,"s /ones1 su* z ! opal1 split up ! light-beams z does a prism1 & %[ a wond]ful exhibition ( prismatic col\r1 :i* is te*nically kn[n z a play ( col\r4 ,! descriptive t]m opalesc5ce is self-sugge/+ z to its orig91 :i* is ! noble or preci\s opal2 ?is radiates brilliant & rapidly *ang+ iridesc5t reflections ( blue1 gre51 yell[ & r$1 all bl5d+ )1 & com+ out (1 a curi\s silky & milky :it5ess1 :i* is altoge!r *>act]i/ic4 ,! moon/one is ano!r example ( ?is peculi> feature :i* is possess$ 9 a m or less degree by all ! /ones 9 ! class ( pellucid jewels1 b no /one or gem c 9 any way ev5 rival ! curi\s mixture ( opaqu5ess1 transluc5cy1 silk9ess1 milk9ess1 fire1 & ! /eadfa/ *angeable & prismatic brilliance ( col\r ( ! preci\s opal4 ,! o!r six v>ieties ( opal are mu* inf]ior 9 _! /range mixture ( ^! anomalies ( light & col\r4 ,giv5 9 ord] ( value1 we h z ! second1 ! fire opal ) a r$ reflection1 &1 z a rule1 t only4 ,! ?ird 9 value is ! common opal1 ) ! col\rs ( gre51 r$1 :ite & yell[1 b ?is is easily di/+ui%able f ! noble or preci\s v>iety 9 t ! common opal does n possess t wond]ful play ( col\r4 ,! f\r? v>iety is call$ ! semi-opal1 :i* is really l ! ?ird v>iety1 ! common1 b ( a poor] quality & m opaque4 ,! fif? v>iety 9 ord] ( value1 is t kn[n z ! hydrophane1 :i* has an int]e/+ *>act]i/ic 9 becom+ transp>5t :5 imm]s$ 9 wat]1 & only !n4 ,! six? is ! hyalite1 :i* has b a glassy or vitre\s lu/re1 & is f\nd almo/ exclusively 9 ! =m ( globules1 or clu/]s ( globules1 some:at aft] ! =m & size ( bun*es ( grapes2 h5ce ! "n botryoidal is (t5 appli$ to ?is v>iety4 ,! la/ & commone/ ( all ! sev5 v>ieties ( opal is some:at aft] ! %ape ( a kidney 7r5i=m71 or o!r irregul> %ape1 occasionally almo/ transp>5t1 b m (t5 some:at transluc5t1 & v (t5 opaque4 ,?is sev5? class is call$ m5ilite1 be+ really an opal9e =m ( qu>tz1 orig9ally f\nd at ,m5ilmontant1 h5ce its "n 7,m5il1 & ,greek li?os1 /one74 ,x is a curi\s blue on ! ext]ior ( ! /one1 br[n inside4 ,hi/ory records _m magnific5t & valuable opals1 n ! lea/ ( :i* 0 t ( ,nonius1 :o decl9$ to give x to ,m>k ,antony1 *oos+ exile r ?an "p ) s r>e a jewel1 :i* ,pl9y describes z be+ exi/5t 9 8 day1 & ( a value :i*1 9 pres5t ,engli% computation1 w\ld exce$ "o hundr$ ?\s& p\nds4 ,_m o!r /ones possess "o or m prop]ties ( ! opal1 & are !re=e consid]$ m or less opalesc5t4 ,?is play ( col\r & opalesc5ce1 mu/ n be confus$ ) *ange ( col\r4 ,! two fir/ appe> mo/ly 9 spots & 9 brilliant po9ts or fla%es ( col\r$ light1 or fire z x is t]m$4 ,?is fire is con/antly on ! move1 or play+1 :]eas *ange ( col\r1 ?\gh n greatly dissimil>1 is :5 ! fire m]ely travels ov] broad] surfaces1 ea* col\r rema9+ con/ant1 su* z :5 directly mov+ ! /one1 or turn+ x1 :5 ! broad mass ( col\r$ light sl[ly *anges1 usually to its complem5t>y4 ,?us 9 ?is class ( /one1 subject to *ange ( col\r1 a gre5 light is usually foll[$ by its complem5t>y1 r$1 yell[ by purple1 blue by orange1 gre5 by br[n1 orange by grey1 purple by brok5 gre51 ) all ! int]m$i>y %ades ( ea*4 ,?us :5 ! l9e ( sight is alt]$1 or ! /one mov$1 nev] o!rwise1 ! col\rs *ase "o ano!r ov] ! surface ( ! gem1 & mo/ly 9 broad spla%es2 b 9 ^? gems possess+ play ( col\r1 /rictly speak+1 :il/ ! /one itself rema9s p]fectly /ill1 & ! sight is fix$ unwav]+ly ^u x1 ! pulsations ( ! blood 9 ! eyes1 ) ! natural movem5ts ( ! eyes & eyelids1 ev5 9 a fix$1 /eady glance1 are q suffici5t to create 9 ! /one a display ( sp>ks & spla%es ( beautiful fi]y light & col\r at e tremor4 ,! t]m iridesc5ce is us$ :5 ! display ( col\r is se5 on ! surface1 r ?an com+ out ( ! /one itself4 ,! cause ( ?is is a natural1 or 9 "s cases an accid5tal1 break+ ( ! surface ( ! /one into num]\s cobweb-l cracks2 ^! are (t5 ( microscopic f95ess1 only p]ceptible "u mod]ately high p[]s4 ,nev]!less !y are q suffici5t to int]f]e ) & refract ! light rays & to split !m up prismatically4 ,9 "s inf]ior /ones ?is same effect is caus$ or obta9$ by ! application ( a g5tle heat1 imm]sion 9 *emicals1 subjection to ,x rays & o!r /rong electric influ5ce1 & 9 _m o!r ways4 ,z a result1 ! /one is v slightly exp&$1 & z ! molecules sep>ate1 !re appe> on ! surface ?\s&s1 p]haps millions1 ( microscopic fissures runn+ at all angles1 s t no matt] f :at position ! /one may be view$1 a great numb] ( ^! fissures are c]ta9 to split up ! light into prismatic col\rs caus+ brilliant iridesc5ce4 ,simil> fissures may (t5 be se5 ) ! nak$ eye on glass1 especially if scor*$ or cool$ too rapidly 7*ill$71 & on ! surface ( cle> sp> & mica1 _! effects be+ ( extreme int]e/1 f a col\r po9t ( view1 at lea/4 ,,*apt] ,,vii4 ,,physical ,,prop]ties4 ,e--,,h>dness4 ,h>dness is p]haps "o ( ! mo/ important features 9 a /one1 especially ^? ( ! gem s]ies1 = no matt] h[ col\r1 lu/re1 g5]al beauty & ev5 r>ity may entitle a /one to ! designation preci\s1 unless x possesses great h>dness x _c be us$ z a gem or jewel4 ,consequ5tly1 ! h>dness ( jewels is a matt] ( no small importance1 & by d9t ( indefatigable rese>*1 9 te/s & comp>ison1 all kn[n preci\s /ones h be5 classifi$ 9 v>i\s scales or degrees ( h>dness4 ,! mo/ popul> & reliable table is t ( ,mohs1 9 :i* he takes talc z ! s(te/ ( ! r>] m9]als & classes ?is z ,no4 #a2 f t he goes by gradual /eps to ! diamond1 ! h>de/ ( ! /ones1 :i* he calls ,no4 #aj1 & betwe5 ^! two all o!r gems are plac$4 ,"h is giv5 a complete li/ ( ,mohs's arrangem5t ( /ones1 accord+ to _! h>dness1 beg9n+ at ,no4 #a1 ?us3-- ,talc #a ,rock salt #b ,amb] #b-a_/b ,calcite #c ,mala*ite #c-a_/b ,jet #c-a_/b ,fluorsp> #d ,apatite #e ,dioptase #e ,kyanite 7v>i\s7 #e-g ,haueynite #e-a_/b ,haematite #e-a_/b ,lapis lazuli #e-a_/b ,moldavite 7v>i\s7 #e-a_/b-f-a_/b ,rhodonite #e-a_/b-f-a_/b ,obsidian #e-a_/b ,sph5e #e-a_/b ,opal 7v>i\s7 #e-a_/b-f-a_/b ,nephrite #e-c_/d ,*rysolite #f-g ,felsp> #f ,adul>ia #f ,amazon /one #f ,diopside #f ,iron pyrites #f ,labradorite #f ,turquoise #f ,spodum5e #f-a_/b-g ,! ,*alc$ony gr\p :i* embraces ! ,agate1 ,c>nelian1 etc4 #f-a_/b ,demantoid #f-a_/b ,epidote #f-a_/b ,idocrase #f-a_/b ,g>nets 7see also ,r$ ,g>nets bel[7 #f-a_/b-g-a_/b ,ax9ite #f-c_/d ,jadeite #f-c_/d ,qu>tz1 includ+ ,rock-cry/al1 ,ame?y/1 ,jasp]1 ,*rysoprase ,citr9e1 etc4 #g ,jade #g ,di*orite 7wat] sapphire7 #g-g-a_/b ,cordi]ite #g-a_/d ,r$ ,g>nets 7see also ,g>nets above7 #g-a_/d ,t\rmal9e #g-a_/d ,&alusite #g-a_/b ,euclase #g-a_/b ,/aurolite #g-a_/b ,zircon #g-a_/b ,em]ald1 ,aquam>9e1 or ,b]yl #g-c_/d ,ph5akite #g-c_/d ,sp9el #h ,topaz #h ,*rysob]yl #h-a_/b ,! ,corundum gr\p embrac+ ! ,ruby1 ,sapphire1 etc4 #i ,diamond #aj 7,see also li/ ( /ones1 arrang$ 9 _! respective col\rs1 9 ,*apt] ,,xii47 ,! me?od ( te/+ is v simple4 ,a repres5tative selection ( ! above /ones1 ea* ) a %>p edge1 is kept = ! purpose ( scrat*+ & be+ scrat*$1 & ^? usually set ap>t = te/s 9 ! v>i\s gr\ps1 are z foll[s3-- #a ,talc #b ,rock-salt1 or ,gypsum #c ,calcite #d ,fluorsp> #e ,apatite #f ,felsp> #g ,qu>tz #h ,topaz #i ,corundum #aj ,diamond ,! /one "u exam9ation may p]haps fir/ be some:at r\ghly classifi$ by its col\r1 cleavage1 & g5]al %ape4 ,"o ( ^! /&>d /ones is !n g5tly rubb$ across its surface & !n o!rs ( increas+ly high] degrees1 till no scrat* is evid5t "u a magnify+ glass4 ,?us if qu>tz ceases to scrat* x1 b a topaz w d s1 ! degree ( h>dness mu/ lie betwe5 #g & #h4 ,!n we rev]se ! process3 ! /one is pass$ ov] ! /&>d1 & if bo? qu>tz & topaz are scrat*$1 !n ! /one is at lea/ equal 9 h>dness to ! topaz1 & its classification becomes an easy matt]4 ,in/ead ( /ones1 "s exp]ts use v>i\sly-temp]$ ne$les ( diff]5t qualities & compositions ( iron & /eel4 ,= in/ance1 a f9ely-temp]$ ord9>y /eel ne$le w cut up to ,no4 #f /ones2 "o made ( tool /eel1 up to #g2 "o ( manganese /eel1 to #g-a_/b2 "o made ( high-spe$ tool /eel1 to #h & #h-a_/b1 & s on1 accord+ to temp]2 s t f ! scrat* :i* c be made ) ! f+]-nail on mica1 to ! h>dness ( ! diamond1 :i* diamond alone w scrat* readily1 ! /ones may be pick$ out1 classifi$ & te/$1 ) un]r+ accuracy4 ,x w ?us be se5 h[ impossible x is1 ev5 9 ?is "o ( _m te/s1 = an exp]t to be deceiv$ 9 ! pur*ase ( preci\s /ones1 except ?r\gh gross c>elessness--a fault seldom1 if ev]1 met ) 9 ! trade4 ,= example--a piece ( rock-cry/al1 *emically col\r$1 & cut to repres5t a ruby1 might appe> s l "o z to deceive a novice1 b ! m]e application to its surface ( a real ruby1 :i* is h>dness #i1 or a ,no4 #i ne$le1 w\ld reveal too deep or p[d]y a scrat*2 also its possibility ( be+ scrat*$ by a topaz or a ,no4 #h ne$le1 w\ld alone prove x false1 = ! corundum gr\p1 be+ h>d] ?an ,no4 #h1 c\ld n be scrat*$ by x4 ,s w\ld ! exp]t g d[n ! scale1 ! t9y scrat*es becom+ fa9t] z he desc5d$1 because he w\ld be approa*+ m ne>ly ! h>dness ( ! /one "u te/1 till he arriv$ at ! felsp>1 ,no4 #f1 :i* w\ld be too s(t to scrat* x1 yet ! /one w\ld scrat* ! felsp>1 b n zircon or &alusite1 #g-a_/b1 or topaz1 #h1 s t 8 te/s w\ld at once classify ! /one z a piece ( cut & col\r$ qu>tz1 ?us confirm+ :at he w\ld1 at ! fir/ sight1 h suspect$ x to be4 ,! /&>d /ones !mselves are mu* m c]ta9 9 results ?an ! ne$les1 :i* latt]1 ?\gh well select$ & temp]$1 are n altoge!r reliable1 especially 9 ! m delicate di/9ctions ( pick+ out ! h>de/ ( c]ta9 /ones ( ! same k9d1 9 :i* cases only ! exp]t judge c decide ) exactness4 ,accurate 9 ?is ! exp]t always is1 = he judges by ! s\nd & dep? ( 8 cut1 & by ! am\nt & quality ( ! p[d]1 (t5 call+ ! microscope to 8 aid1 s t :5 ! decision is made f9ally1 !re is nev] ! lea/ d\bt ab\t x4 ,rapidly z ^! te/s c be made1 !y are extremely reliable1 & %\ld ! /one be ( great value1 x is also subject$ to o!r un]r+ te/s ( extreme sev]ity1 any "o ( :i* w\ld prove x false1 if x *anc$ to be s1 ?\gh "s /ones are manufactur$ & col\r$ s clev]ly t to all b ! exp]t judge & exp]i5c$ deal]1 !y w\ld pass well = ! g5u9e4 ,9 ,mohs's li/ x w be se5 t sev]al /ones v>y consid]ably1 ! opal1 = in/ance1 hav+ a degree ( h>dness f #e-a_/b to #f-a_/b inclusive4 ,all /ones diff] slightly1 ?\gh almo/ all may be said to fit _! position 9 ! scale2 b 9 ! case ( ! opal1 ! diff]5ce %[n is p>tly due to ! _m v>ieties ( ! /one1 z describ$ 9 ! la/ *apt]4 ,9 apply+ ?is te/ ( h>dness to a cut gem1 x w be notic$ t "s p>ts ( ! same /one seem to scrat* m readily ?an o!rs1 su* z on a facet at ! side1 :i* is (t5 s(t] ?an ^? ne>e/ ! wide/ "p ( ! /one1 :]e ! claws1 :i* hold x 9 its sett+1 usually come4 ,?is portion is call$ ! girdle1 & x is on ^! girdle facets t ! scrat*es are g5]ally made4 ,?is v>iation 9 h>dness is mo/ly caus$ by cleavage1 ^! cleavage planes %[+ a m>k$1 ?\gh (t5 b slight1 diff]5ce 9 ! scrat*1 :i* diff]5ce is felt r ?an se54 ,9 addition to ! peculi> feel ( a cutt+ scrat*1 is ! s\nd ( x4 ,on a s(t /one be+ cut by a h>d "o1 little or no s\nd is he>d1 b !re w =m a pl5tiful supply ( p[d]1 :i*1 on be+ bru%$ (f1 reveals a m or less deep incision4 ,b z ! /ones approa* "o ano!r 9 h>dness1 !re w be little p[d] & a consid]able increase 9 ! noise2 = ! h>d] are ! /ones1 cutt+ & be+ cut1 ! l\d] w be ! s\nd & ! less ! p[d]4 ,an example ( ?is diff]5ce is evid5t 9 ! cutt+ ( ord9>y glass ) a set or glazi]'s diamond1 & ) a nail4 ,if ! diamond is held prop]ly1 !re w be he>d a curi\s s\nd l a ke51 drawn-out kiss1 ! diamond be+ consid]ably h>d] ?an ! mat]ial x cut4 ,an altoge!r diff]5t s\nd is t produc$ by ! scrat*+ ( glass ) a nail4 ,9 ?is case1 ! relative diff]5ce 9 h>dness betwe5 ! two is small1 s t ! glass c only be scrat*$ & n cut by ! nail2 x is too h>d = t1 s ! noise is mu* great] & becomes a scree*4 ,exp]i5ce1 !re=e1 makes x possible to tell to a trifle1 at ! fir/ contact1 ( :at ! /one is compos$1 & 9 :i* class x %\ld be plac$1 by ! m]e feel ( ! scrat*1 ! dep? ( x1 ! am\nt & k9d ( p[d] x leaves1 & above all1 by ! s\nd made1 :i*1 ev5 9 ! t9ie/ scrat*1 is q *>act]i/ic4 ,,*apt] ,,viii4 ,,physical ,,prop]ties4 ,f--,,specific ,,gravity4 ,! fix+ ( ! specific gravity ( a /one also det]m9es its gr\p position ) reg>d to weight2 its col\r & o!r *>act]i/ics def9+ ! actual /one4 ,?is is a safe & v common me?od ( prov+ a /one1 s9ce its specific gravity does n v>y m ?an a po9t or s 9 diff]5t specim5s ( ! same /one4 ,!re are sev]al ways ( arriv+ at ?is1 su* z by weigh+ 9 balances 9 ! usual mann]1 by displacem5t1 & by imm]sion 9 liquids ! specific gravity ( :i* are kn[n4 ,cork is ( less specific gravity ?an wat]1 !re=e x floats on ! surface ( t liquid1 :]eas iron1 be+ heavi]1 s9ks4 ,s t by *ang+ ! liquid to "o light] ?an cork1 ! cork w s9k 9 x z does iron 9 wat]2 9 ! second in/ance1 if we *ange ! liquid to "o heavi] ?an iron1 ! iron w float on x z does cork on wat]1 & exactly z an ord9>y flat-iron w float on quicksilv]1 bobb+ up & d[n l a cork 9 a tumbl] ( wat]4 ,if1 !re=e1 solutions ( kn[n b v>y+ d5sities are comp\nd$1 x is possible to tell almo/ to exactitude ! specific gravity ( any /one dropp$ into !m1 by ! position !y assume4 ,?us1 if we take a solution ( pure me?yl5e iodide1 :i* has a specific gravity ( #c4biha1 & into ?is drop a few /ones select$ indiscrim9ately1 ! effect w be curi\s3 fir/1 "s w s9k plump to ! bottom l lead2 second1 "s w fall s f> quickly1 !n rema9 = a consid]able "t fairly /ation>y2 ?ird1 "s w s9k v sl[ly2 f\r?1 "s w be p>tially imm]s$1 t is1 a portion ( _! sub/ance be+ above ! surface ( ! liquid & a portion cov]$ by x2 fif?1 "s w float on ! surface )\t any app>5t imm]sion4 ,9 ! fir/ case1 ! /ones w be mu* heavi] ?an #c4biha2 9 ! second1 ! /ones w be ab\t #c4ej2 9 ! ?ird & f\r? in/ances1 ! /ones w be ab\t ! same specific gravity z ! liquid1 :il/ 9 ! fif?1 !y w be mu* light]1 & ?us a r\gh b tol]ably accurate isolation may be made4 ,on c]ta9 /ones be+ extract$ & plac$ 9 o!r liquids ( light] or d5s] specific gravity1 z ! case may be1 _! prop] classification may easily be arriv$ at1 & if ! results are *eck$ by actual weight1 9 a specific gravity balance1 !y w be f\nd to be fairly accurate4 ,! solution commonly us$ = ! heavie/ /ones is a mixture ( nitrate ( ?allium & nitrate ( silv]4 ,?is d\ble nitrate has a specific gravity ( #d4gifc1 !re=e su* a /one z zircon1 :i* is ! heavie/ kn[n1 w float 9 x4 ,= use1 ! mixture %\ld be slightly w>m$ till x runs ?9 & cle>2 ?is is necess>y1 because at #fj deg4 7tak+ ?is z ord9>y atmosph]ic temp]ature7 x is a /iff mass4 ,a light] liquid is a mixture ( iodide ( m]cury 9 iodide ( potassium1 b ?is is su* an extremely corrosive & dang]\s mixture1 t ! m common solution is "o 9 :i* me?yl5e iodide is saturat$ ) a mixture ( iod(orm until x %[s a specific gravity ( #c4fja2 & by us+ ! me?yl5e iodide alone1 9 its pure /ate1 x hav+ a specific gravity ( #c4biha1 ! /ones to t weight c be isolat$1 & by dilut+ ?is ) b5zole1 its weight c be br\ght d[n to t ( ! b5zole itself1 z 9 ! case ( ,son/adt's solution4 ,?is solution1 9 full /&>d /r5g?1 has a specific gravity ( #c4aghi1 b may be weak5$ by ! addition ( di/ill$ wat] 9 v>y+ proportions till ! weight becomes almo/ t ( wat]4 ,kn[+ ! specific gravity ( all /ones1 & divid+ !m into six gr\ps1 by tak+ a s]ies ( /&>d solutions select$ f "o or o!r ( ! above1 & ( kn[n specific gravity1 we c judge ) accuracy if any /one is :at x is suppos$ to be1 & classify x correctly by its m]e float+ or s9k+ :5 plac$ 9 ^! liquids4 ,beg9n+ !n ) ! pure d\ble nitrate ( silv] & ?allium1 ?is w isolate ! /ones ( less specific gravity ?an #d4gifc1 & tak+ ! light] solutions & /&>dis+ !m1 we may get sev5 solutions :i* w isolate ! /ones z foll[s3-- ,a %[s ! /ones :i* h #d4gifc a specific gravity ov] ,b #c4gj & "u #d4gifc ,c #c4ej #c4gj ,d #c4jj #c4ej ,e #b4ej #c4jj ,f #b4jj #b4ej ,g -- -- "u #b4jj ,!re=e ea* liquid w isolate ! /ones 9 its own gr\p by compell+ !m to float on its surface2 comm5c+ ) ! heavie/ & giv+ to ! gr\ps ! same lett]s z ! liquids1 x is se5 t-- ,gr\p ,a4--,isolates gems ) a specific gravity ( #d4gifc & ov] #d4gj2 9 ?is gr\p is plac$ zircon1 ) a specific gravity ( f #d4gj to #d4hh4 ,gr\p ,b4--,/ones ^: specific gravity lies betwe5 #c4gj & "u #d4gifc4 ,g>nets1 _m v>ieties4 ,see ,gr\p ,d bel[4 ,alm&9e #d4aa & occasionally to #d4be ,ruby #d4jgc #d4jhj ,sapphire #d4jdi #d4jfj ,corundum #c4ij #d4af ,cape ,ruby #c4hfa ,demantoid #c4hae ,/aurolite #c4gce ,mala*ite #c4gaj & occasionally to #c4iif ,gr\p ,c4--,/ones ^: specific gravity lies betwe5 #c4ej & "u #c4gj4 ,pyrope 7av]age7 #c4fhb ,*rysob]yl #c4fhi & occasionally to #c4geb ,sp9el #c4fad #c4fed ,kyanite #c4fji #c4fhh ,hessonite #c4fjc #c4fea ,diamond #c4ejb #c4efd ,topaz #c4ejj #c4ebj ,gr\p ,d4--,/ones ^: specific gravity lies betwe5 #c & "u #c4ej4 ,rhodonite #c4dac & occasionally to #c4fag ,g>nets #c4djj #d4ejj ,epidote #c4cfj #c4dhj ,sph5e #c4cdh & occasionally to #c4dbj ,idocrase #c4cdf #c4daj ,oliv9e #c4ccd #c4cfh ,*rysolite #c4caf #c4ebh ,jade #c4cjj #c4cha ,jadeite #c4bii ,ax9ite #c4bie ,dioptase #c4bhi ,diopside #b4bgi ,t\rmal9e 7yell[7 #c4baj ,&alusite #c4bjd ,apatite #c4aij ,t\rmal9e 7,blue & ,violet7 #c4afj ,t\rmal9e 7,gre57 #c4adh 7,r$7 #c4ajj ,spodum5e #c4acj & occasionally to #c4bjj ,euclase #c4jij ,fluorsp> #c4jca & occasionally to #c4bjj ,t\rmal9e 7,col\rless7 #c4jbi ,t\rmal9e 7,blu% ,rose7 #c4jbd ,t\rmal9e 7,black7 #c4jbd & occasionally to #c4cjj ,nephrite #c4jai ,gr\p ,e4--,/ones ^: specific gravity lies betwe5 #b4ej & "u #c4jjj4 ,ph5akite #b4ife ,turquoise #b4hjj ,b]yl #b4gji & occasionally to #b4ha ,aquam>9e #b4gja #b4hj ,labradorite #b4gjj ,em]ald #b4fij ,qu>tz #b4fgj ,*rysoprase #b4fgj ,jasp] #b4ffh ,ame?y/ #b4ffa ,horn/one #b4feh ,citr9e #b4feh ,cordi]ite #b4fda ,agate #b4faj ,*alc$ony #b4eih & occasionally to #b4faj ,adul>ia #b4efg ,rock-cry/al #b4eba & occasionally to #b4gie ,gr\p ,f4--,/ones ^: specific gravity lies betwe5 #b4jj & "u #b4ej4 ,haueynite #b4dgj & occasionally to #b4dia ,lapis lazuli #b4dfa ,moldavite #b4ced ,opal #b4afj & accord+ to v>iety to #b4bhc 7,fire ,opal7 #b4baj 7av]age7 ,gr\p ,g4--,/ones ^: specific gravity is "u #b4jj4 ,jet #a4cdh ,amb] #a4jjj 7,see also li/ ( /ones1 arrang$ 9 _! respective col\rs1 9 ,*apt] ,,xii47 ,9 _m ( ^! cases ! specific gravity v>ies f 4#aa to 4#bj1 b ! above are ! av]age figures obta9$ f a numb] ( samples specially & sep>ately weigh$4 ,9 "s in/ances ?is diff]5ce may cause a slight ov]lapp+ ( ! gr\ps1 z 9 gr\p ,c1 :]e ! *rysob]yl may weigh f #c4fhi to #c4geb1 ?us br++ ! heavi] v>ieties ( ! /one into gr\p ,b1 b 9 all cases :]e ov]lapp+ occurs1 ! col\r1 =m1 & ! self-evid5t "* ( ! /one are 9 !mselves suffici5t = classification1 ! specific gravity prov+ g5u95ess4 ,?is is especially appreciat$ :5 x is rememb]$ t s f> sci5ce has be5 unable 7except 9 v r>e in/ances ( no importance7 to manufacture any /one ( ! same col\r z ! g5u9e & at ! same "t ( ! same specific gravity4 ,ei!r ! col\r & *>act]i/ics suff] 9 obta9+ ! requir$ weight or d5sity1 or if ! col\r & o!r prop]ties ( an artificial /one are made closely to resemble ! real1 !n ! specific gravity is s greatly diff]5t1 ei!r m or less1 z at once to /amp ! jewel z false4 ,9 ! v few exceptions :]e *emically-made gems ev5 approa* ! real 9 h>dness1 col\r1 specific gravity1 c41 !y co/ s mu* to obta9 & ! difficulties ( production are s great t !y become m]e *emical curiosities1 f> m co/ly ?an ! real gems4 ,fur!r1 !y are s mu* subject to *emical action1 & are s susceptible to _! surr\nd+s1 t _! purity & /ability _c be ma9ta9$ = long ev5 if kept airtight2 consequ5tly ^! ultra-p]fect imitations are ( no comm]cial value :atev] z jewels1 ev5 ?\gh !y may successfully )/& two or ?ree te/s4 ,,*apt] ,,ix4 ,,physical ,,prop]ties4 ,g--,,heat4 ,ano!r me?od ( isolat+ c]ta9 /ones is by ! action ( heat-rays4 ,rememb]+ our lessons 9 physics we recall t j z light-rays may be refract$1 absorb$1 or reflect$1 accord+ to ! m$ia ?r\gh :i* !y are caus$ to pass1 s d heat-rays possess simil> prop]ties4 ,!re=e1 if heat-rays are project$ ?r\gh preci\s /ones1 or br\ght to be> on !m 9 "s o!r mann] ?an by simple projection1 !y w be refract$1 absorb$1 or reflect$ by ! /ones 9 ! same mann] z if !y 7 light-rays1 & j z c]ta9 /ones all[ light to pass ?r\gh _! sub/ance1 :il/ o!rs are opaque1 s d "s /ones (f] no resi/ance to ! passage ( heat-rays1 b all[ !m free movem5t ?r\gh ! sub/ance1 :il/1 9 o!r cases1 no passage ( heat is possible1 ! /ones be+ z opaque to heat z to light4 ,inde$1 ! prop]ties ( light & heat are 9 _m ways id5tical1 ?\gh ! te/ by heat mu/ 9 all cases give place to t by light1 :i* latt] is by f> ( ! great] importance 9 ! judg+ & isolation ( preci\s /ones4 ,x w readily be und]/ood t 9 ! spectrum ! out] or extreme light-rays at ea* side are m or less b5t or div]t$1 b ^? ne>e/ ! c5tre are comp>atively /raight1 s t1 z be=e rem>k$1 ^! c5tral rays are tak5 z be+ ! /&>d ( light-value4 ,?is div]g5ce or refraction is great] 9 "s /ones ?an 9 o!rs1 & to x ! diamond1 z an example1 owes its *ief *>m4 ,9 j su* mann] d c]ta9 /ones refract1 absorb1 or reflect heat2 ?us amb]1 gypsum1 & ! l1 are practically opaque to heat-rays1 9 contra/ ) ^? ( ! nature ( fluorsp>1 rock-salt1 c41 :i* are receptive4 ,heat passes ?r\gh ^! z easily z does light ?r\gh a diamond1 su* /ones be+ class$ z dia!rmal 7to heat ?r\gh74 ,s t all dia!rmal /ones are easily p]meable by radiant heat1 :i* passes ?r\gh !m exactly z does light ?r\gh transp>5t bodies4 ,o!rs1 aga91 are bo? s+le & d\ble refract+ to heat-rays1 & x is int]e/+ to note ! heat-p5etrat+ value z comp>$ ) ! refractive indexes ( ! /one4 ,9 ! foll[+ table w be f\nd ! refractive indexes ( a selection ( s+le & d\ble refractive /ones1 ! figures = ,light be+ tak5 f a /&>d li/4 ,! second column %[s ! refractive p[] ( heat1 appli$ to ! actual /ones1 & consi/+ ( a f9e p5cil bl[pipe-flame1 "o l9e 7! "o twelf? "p ( an in*7 9 l5g? 9 ea* case4 ,?is li/ mu/ be tak5 z approximate1 s9ce 9 _m in/ances ! te/ has be5 made on "o /one only1 )\t possibility ( obta9+ an av]age2 & z /ones v>y consid]ably1 ! figures may be rais$ or l[]$ slightly1 or p]haps ev5 *ang$ 9 class1 because 9 "s /ones ! lea/ /a9 or impurity may cause ! heat effects to be alt]$ greatly 9 _! "*1 & ev5 to become s+ly or d\bly refract+1 opaque or transp>5t1 to heat-rays1 accord+ to ! nature ( ! impurity or to "s slight *ange 9 ! cry/all9e /ructure1 & s on4 ,selection ( ,s+ly refract+ /ones4 ,indexes ( ,rays ( ,,light4 ,,heat4 ,fluorsp> #a4dcf #d4aj v>ies ,opal #a4dgi #b4aj ,sp9el #a4gbf #a4jj ,alm&9e #a4gfd #a4jj ,diamond #b4dca #f4aa d\ble ,selection ( ,d\bly refract+ /ones4 ,indexes ( ,rays ( ,,light4 ,,heat4 ,qu>tz #a4ede #d4g s+le & d\ble ,b]yl #a4ege #a4j v>ies consid]ably ,topaz #a4fce #d4a ,*rysob]yl #a4gfe #a4a ,ruby #a4idi #e4a s+le & d\ble ,! t\rmal9e has a light-refractive index ( #a4fc1 ) a heat index ( none1 be+ to heat-rays completely opaque4 ,! refractive index ( gypsum is #a4ed1 b heat none1 be+ opaque4 ,! refractive index ( amb] is #a4ea1 b heat none1 be+ opaque4 ,9 "s ( ! specim5s ! gypsum %[$ a heat-p5etration index ( #j4jja1 & amb] ( #j4jef1 b mo/ly n )9 ! ?ird po9t4 ,9 all cases ! heat-p5etration & refraction 7 %[n by electric record]s4 ,^! figures are ! av]age ( ^? obta9$ f te/s made 9 "s cases on sev]al /ones ( ! same k9d1 & also on isolat$ specim5s4 ,n only does ! p[] ( ! /one to conduct heat v>y 9 diff]5t /ones ( ! same k9d or v>iety1 z already expla9$1 b !re is se5 a rem>kable diff]5ce 9 value1 accord+ to ! spot on :i* ! heat is appli$1 s t on "o /one !re is (t5 se5 a conductivity v>y+ betwe5 #j4ae to #d4gj4 ,?is is ow+ to ! diff]5ces ( expansion due to ! tempor>y di/urbance ( its cry/all9e /ructure1 br\ght ab\t by ! appli$ heat4 ,?is w be evid5t :5 heat is appli$ on ! axes ( ! cry/al1 on _! faces1 angles1 l9es ( symmetry1 etc41 etc41 ea* "o ( :i* gives diff]5t results1 n only z to value 9 conductivity1 b a result :i* v>ies 9 a curi\s degree1 out ( all proportion to ! heat appli$4 ,9 _m cases a slight dim9ution 9 appli$ heat gives a great] conductivity1 :il/ 9 o!rs a slight rise 9 ! temp]ature ( ! heat de/roys its conductivity altoge!r1 & r5d]s ! /one q opaque to heat-rays4 ,?is anomaly is due entirely to ! alt]ation ( cry/all9e /ructure1 :i*1 9 ! "o case1 is s *ang$ by ! dim9ution 9 heat z to cause ! cry/als to be s plac$ t !y become dia!rmal1 or transp>5t to heat-rays2 :il/1 9 ! o!r in/ance1 ! cry/als :i* s arrange !mselves z to be dia!rmal are1 by a slightly increas$ temp]ature1 some:at displac$1 & reflect1 or o!rwise oppose ! direct passage ( heat-rays1 :i*1 at ! l[] temp]ature1 obta9$ free passage4 ,?us c]ta9 /ones become bo? opaque & dia!rmal1 & z ! heat is caus$ to v>y1 s d !y %[ ! complete gamut betwe5 ! two extremes ( total opacity & complete transp>5cy to heat-rays4 ,= ! purpose "u consid]ation1 ! temp]ature ( ! p5cil ( heat appli$ to ! /ones 9 _! sev]al portions 0 kept con/ant4 ,x w be se51 !re=e1 t no great reliance c be plac$ on ! heat te/ z appli$ to preci\s /ones4 ,,*apt] ,x4 ,,physical ,,prop]ties4 ,h--,,magnetic ,,& ,,electric ,,influ5ces4 ,! ^w electricity is d]iv$ f ! ,greek elektron1 :i* 0 ! "n = amb]1 a m9]alis$ res9 ( ext9ct p9e-trees4 ,x 0 well-kn[n to ! p ( pre-hi/oric times2 lat] to ! e>ly ,egyptians1 &1 at a /ill lat] date1 we h record$ h[ ,?ales--! ,greek philosoph]1 :o liv$ ab\t ! close ( ! #g? ,c5tury ,b4,c41 & 0 "o ( ! sev5 wise m5--discov]$ ! peculi> prop]ty :i* we call electricity by rubb+ dry silk on amb]4 ,_m /ones are capable ( exhibit+ ! same ph5om5on1 n only by friction1 z 9 ,?ales's exp]im5t1 b also "u ! influ5ce ( light1 heat1 magnetism1 *emical action1 pressure1 etc41 & ( hold+ or reta9+ ?is induc$ or add$ p[] = a long or %ort p]iod1 accord+ to conditions & environm5t4 ,if a small pi? ball is susp5d$ f a non-conduct+ support1 x =ms a simple & ready means ( te/+ ! electricity 9 a /one4 ,accord+ to :e!r ! ball is repell$ or attract$1 s is ! electricity 9 ! /one made evid5t1 ?\gh ! electroscope gives ! bett] results4 ,by ei!r ( ^! me?ods x w be f\nd t "s ( ! /ones are m capable ( giv+ & receiv+ *>ges ( electricity ?an are o!rs2 also t "s are *>g$ ?r\gh\t ) "o k9d only1 ei!r positive or negative1 :il/ o!rs h bo?1 becom+ pol>is$ electrically1 hav+ "o portion ( _! sub/ance negative1 ! o!r positive4 ,= in/ance1 amb]1 z is well kn[n1 produces negative electricity "u ! influ5ce ( friction1 b 9 almo/ all cut /ones1 o!r ?an amb]1 ! electricity produc$ by ! same means is positive1 :]eas 9 ! uncut /ones ! electricity is negative1 ) ! exception ( ! diamond1 9 :i* ! electricity is positive4 ,:5 heat$1 "s /ones lose _! electricity2 o!rs develop x1 o!rs h x rev]s$1 ! positive becom+ negative & vice v]sa2 o!rs aga91 :5 heat$1 become p[]fully magnetic & assume /rong pol>ity4 ,:5 electricity develops "u ! influ5ce ( heat1 or is 9 any way connect$ ) a ris+ or fall+ ( temp]ature 9 a body1 x is call$ pyro-electricity1 f ! ,greek ^w pyros1 fire4 ,! ph5om5on 0 fir/ discov]$ 9 ! t\rmal9e1 & x is obs]v$1 speak+ broadly1 only 9 ^? m9]als :i* are hemimorphic1 t is1 :]e ! cry/als h diff]5t planes or faces at _! two ends1 examples ( :i* are se5 9 su* cry/als z ^? ( ax9ite1 boracite1 smi?sonite1 topaz1 etc41 all ( :i* are hemimorphic4 ,tak+ ! t\rmal9e z an example ( ! pyro-electric m9]als1 we f9d t :5 ?is is heat$ to betwe5 #ej deg4 ,f4 & #cjj deg4 ,f4 x assumes electric pol>ity1 becom+ electrifi$ positively at "o end or pole & negatively at ! opposite pole4 ,if x is susp5d$ on a silk5 ?read f a glass rod or o!r non-conduct+ support 9 a simil> mann] to ! pi? ball1 ! t\rmal9e w be f\nd to h become an excell5t magnet4 ,by te/+ ?is cont9ually z x cools !re w soon be p]ceiv$ a po9t :i* is ( extreme delicacy ( temp]ature1 :]e ! magnetic prop]ties are almo/ 9 abeyance4 ,b z ! t\rmal9e cools yet fur!r1 ?\gh b a fraction ( a degree1 ! magnetic prop]ties *ange2 ! positive pole becomes ! negative1 ! negative hav+ *ang$ to ! positive4 ,x is also int]e/+ to note t if ! t\rmal9e is n w>m$ s high z to rea* a temp]ature ( #ej deg4 ,f41 or is heat$ s /rongly z to exce$ m ?an a few degrees above #cjj deg4 ,f41 !n ^! magnetic prop]ties d n appe>1 z no pol>ity is pres5t4 ,?is pol>ity1 or ! pres5ce ( positive & negative electricity 9 "o /one1 may be /rik+ly illu/rat$ 9 a v simple mann]3--,if a little sulphur & r$-lead1 bo? 9 f9e p[d]1 are %ak5 up toge!r 9 a pap] or simil> bag1 ! mod]ate friction ( p>ticle aga9/ p>ticle electrifies bo?2 "o negatively1 ! o!r positively4 ,if1 !n1 a little ( ?is n[ gold5-col\r$ mixture is g5tly du/$ ov] ! surface ( ! t\rmal9e or o!r /one possess+ electric pol>ity1 a mo/ int]e/+ *ange is at once app>5t4 ,! r$-lead sep>ates itself f ! sulphur & adh]es to ! negative portion ( ! /one1 :il/ ! sep>at$ sulphur is at once attract$ to ! positive end1 s t ! gold5-col\r$ mixture becomes sl[ly trans=m$ into its two sep>ate compon5ts--! brilliant yell[ sulphur1 & ! equally brilliant r$-lead4 ,^! p>ticles =m 9 l9es & waves ar\nd ! respective poles 9 beautiful symmetry1 _! positions correspond+ ) ! directions ( ! l9es ( magnetic =ce1 exactly z w iron fil+s r\nd ! two poles ( a magnet4 ,f ?is x w cle>ly be se5 h[ simple a matt] x is to isolate ! topaz1 t\rmal9e1 & all ! pyro-electric /ones f ! non-pyro-electric1 = sci5ce has n z yet be5 able to give to spuri\s /ones ^! same electric prop]ties1 h[ev] excell5t "s imitations may be 9 o!r respects4 ,fur!r1 almo/ all m9]als lose _! electricity rapidly on exposure to atmosph]ic influ5ces1 ev5 to dry air2 ! diamond reta9s x some:at long] ?an mo/ /ones1 ?\gh ! sapphire1 topaz1 & a few o!rs reta9 x almo/ z long aga9 z ! diamond1 & ^! electric prop]ties are "s ( ! te/s :i* are us$ 9 ! exam9ation ( preci\s /ones4 ,^? /ones :i* %[ electricity on ! application ( pressure are su* z ! fluorsp>1 calcite1 & topaz4 ,) reg>d to magnetism1 ! actual cause ( ?is is n yet kn[n ) c]ta9ty4 ,x is1 ( c\rse1 a self-evid5t fact t ! magnetic iron ore1 :i* is a =m ( p]oxide1 commonly kn[n z magnetite1 or lode/one1 has ! p[] ( attract+ a magnet :5 sw++ free1 or ( be+ attract$ by a magnet1 to acc\nt = :i* _m plausible reasons h be5 advanc$4 ,p]haps ! mo/ reasonable & acceptable ( ^! is t ?is mat]ial conta9s molecules :i* h half _! sub/ance positively & ! o!r half negatively magnetis$4 ,sub/ances s compos$1 ( :i* magnets are an example1 may be made ! means ( magnetis+ o!r sub/ances by friction1 )\t !y !mselves suff]+ any loss2 b x is n all sub/ances t w respond to ! magnet4 ,= in/ance1 common iron pyrites1 ,fe,s#b1 is unresponsive1 :il/ ! magnetic pyrites1 :i* v>ies f #e;,fe,s1 ,fe#b,s#c1 to #f;,fe,s1 ,fe#b,s#c1 & is a sulphide ( iron1 is responsive bo? positively & negatively4 ,bismu? & antimony also are inactive1 :il/ almo/ all m9]als conta9+ ev5 a small p]c5tage ( iron w deflect ! magnetic ne$le1 at lea/ "u ! influ5ce ( heat4 ,s t f ! lode/one--! mo/ p[]fully magnetic m9]al kn[n--to ^? m9]als possess+ no magnetic action :atev]1 we h a long1 graduat$ scale1 9 :i* _m ( ! preci\s /ones appe>1 ^? conta9+ iron 9 _! composition be+ m or less responsive1 z already m5tion$1 & t ei!r 9 _! normal /ate1 or :5 heat$1 & always to an ext5t dep5d+ on ! quantity or p]c5tage ( iron !y conta94 ,9 ?is case1 also1 sci5ce has n z yet be5 able to introduce into an artificial /one ! requisite quantity ( iron to br+ x ! same analytically z ! gem x is suppos$ to repres5t1 )\t completely spoil+ ! col\r4 ,s t ! behavi\r ( a /one 9 ! pres5ce ( a magnet1 to ! degree to :i* x %\ld or %\ld n respond1 is "o ( ! important te/s ( a g5u9e /one4 ,,*apt] ,,xi4 ,,! ,,cutt+ ,,( ,,preci\s ,,/ones4 ,z exi/+ 9 a /ate ( nature preci\s /ones d n1 z a rule1 exhibit any ( ^? beautiful & wond]ful prop]ties :i* cause !m to be s admir$ & s\ght aft] z to become ( great intr9sic value1 = _! surfaces h become cl\d$ by innum]able f9e cuts or abrasions1 because ( ! ?\s&s ( ye>s dur+ :i* !y h be5 "u pressure1 or tumbl$ ab\t 9 riv]s1 or subject$ to ! incessant friction caus$ by surr\nd+ sub/ances4 ,all ?is occurr+ above & "u gr\nd has giv5 !m an appe>ance altoge!r diff]5t to t :i* foll[s cutt+ & poli%+4 ,fur!r1 ! %ape ( ! /one becomes alt]$ by ! same means1 & j z ,mi*ael ,angelo's figure 0 already 9 ! m>ble1 z he faceti\sly said1 & all he _h to d 0 to *ip (f :at he did n require till he came to x1 s is ! same process ( cutt+ & poli%+ necess>y to give to ! preci\s /ones _! full value1 & x is ! mann] 9 :i* ^! delicate & difficult op]ations are p]=m$ t is n[ "u consid]ation4 ,j z exp]i5ce & skill are ess5tial to ! obta9+ ( a p]fect figure f ! block ( m>ble1 s mu/ ! cutt+ & poli%+ ( a preci\s /one call = ! greate/ dext]ity ( :i* a workman is capable1 exp]i5ce & skill s great z to be f\nd only 9 ! exp]t1 = 9 /ones ( great value ev5 a slight mi/ake 9 ! %ap+ & cutt+ w\ld probably n only be wa/eful ( ! preci\s mat]ial1 b w\ld utt]ly spoil its beauty1 caus+ incalculable loss1 & de/roy+ altoge!r ! refrangibility1 lu/re & col\r ( ! /one1 ?us r5d]+ x liable to easy fracture3 9 e s5se conv]t+ :at w\ld h be5 a r>e & magnific5t jewel to a comp>atively valueless specim54 ,"o ( ! *ief s]vices r5d]$ by preci\s /ones is t !y may be employ$ z objects ( adornm5t1 !re=e1 ! /one mu/ be cut ( su* a %ape z w all[ ( its be+ set )\t fall+ out ( its fa/5+--n too %all[ or ?91 to make x uns]viceable & liable to fracture1 & 9 ! case ( a transp>5t /one1 n too deep = ! light to p5etrate1 or mu* col\r & beauty w be lo/4 ,aga91 v few /ones are flawless1 & ! position 9 :i* ! flaw or flaws appe> w1 to a great ext5t1 regulate ! %ape ( ! /ones1 = !re are "s positions 9 :i* a slight flaw w\ld be ( small detrim5t1 because !y w\ld take little or no reflection1 :il/ 9 o!rs1 :]e ! reflections g back & =? f facet to facet ?r\gh\t ! /one1 a flaw w\ld be magnifi$ times )\t numb]1 & ! value ( ! /one greatly r$uc$4 ,x is !re=e ess5tial t a flaw %\ld be remov$ :5ev] possible1 b1 :5 ?is is n practicable1 ! exp]t w cut ! /one into su* a %ape z w br+ ! defect into ! lea/ important "p ( ! f9i%$ gem1 or probably sacrifice ! size & weight ( ! orig9al /one by cutt+ x 9 two or m pieces ( su* a %ape t ! cutt+ & poli%+ w oblit]ate ! defective portions4 ,su* a me?od 0 adopt$ ) ! great ,cull9an diamond1 z describ$ 9 ,*apt] ,,iv4 ,f ?is rem>kable diamond a great numb] ( magnific5t /ones 7 obta9$1 ! two *ief be+ ! l>ge/ & heavie/ at pres5t kn[n4 ,"s idea ( ! size ( ! orig9al /one may be ga!r$ f ! fact t ! traditional ,indian diamond1 ! ,great ,mogul1 is said to h weigh$ #bhj c>ats4 ,?is /one1 h[ev]1 is lo/1 & "s exp]ts believe t x 0 divid$1 "p ( x =m+ ! pres5t fam\s ,koh-i-nur2 at any rate1 all trace ( ! ,great ,mogul ceas$ ) ! loot+ ( ,delhi 9 #agci4 ,! ,koh-i-nur weighs a little ov] #ajf c>ats2 be=e cutt+ x weigh$ a %ade ov] #ahf2 ! ,cull9an1 9 ! same /ate1 weigh$ ne>ly #cbed c>ats4 ,?is massive diamond 0 cut into ab\t #bjj /ones1 ! l>ge/1 n[ plac$ 9 ,! ,royal ,sceptre ) ! ,cross1 weigh+ #eaf-a_/b c>ats1 ! second1 n[ plac$ "u ! hi/oric ruby 9 ,! ,imp]ial ,/ate ,cr[n1 weigh+ #cji-c_/af?s c>ats4 ,^! two diamonds are n[ call$ ,! ,/>s ( ,africa4 ,bo? ^! /ones1 b especially ! l>g]1 completely ov]%ad[ ! notori\s ,koh-i-nur1 & not)/&+ ! flaw :i* appe>$ 9 ! orig9al /one1 e "o ( ! result+ pieces1 irrespective ( weight1 is )\t ! slighte/ blemi% & ( ! f9e/ col\r ev] kn[n1 = ! great ,s\? ,african diamond is ( a quality nev] ev5 approa*$ by any exi/+ /one1 be+ ideally p]fect4 ,x requires a some:at elaborate explanation to make cle> ! v>i\s /yles ( cut )\t illu/rations4 ,!y are usually divid$ into two gr\ps1 ) curv$1 & ) flat or plane surfaces4 ,( ! fir/1 ! curv$ surfaces1 opaque & transluc5t /ones1 su* z ! moon/one1 cat's-eye1 etc41 are mo/ly cut en cabo*on1 t is1 dome-%ap$ or semi-circul> at ! top1 flat on ! und]side1 & :5 ! g>net is s cut x is call$ a c>buncle4 ,9 /rongly col\r$ /ones1 :ile ! upp] surface is semi-circul> l ! cabo*on1 ! "u surface is m or less deeply concave1 sometimes foll[+ ! curve ( ! upp] surface1 ! ?ickness ( ! /one be+ 9 t case almo/ p>allel ?r\gh\t4 ,?is is call$ ! holl[ cabo*on4 ,o!r /ones are cut s t ! upp] surface is dome-%ap$ l ! la/ two1 b ! l[] is m or less convex1 ?\gh n s deep z to make ! /one sph]ical4 ,?is is call$ ! d\ble cabo*on4 ,a fur!r v>iety ( cutt+ is kn[n z ! g\tte de suif1 or ! tall[-drop1 :i* takes ! =m ( a some:at flatt5$ or long-focus d\ble-convex l5s4 ,! m complicat$ v>ieties ( cut are ^? appe>+ 9 ! second gr\p1 or ^? ) plane surfaces4 ,a v old =m is ! rose or rosette2 9 ?is ! extreme upp] c5tre1 call$ ! cr[n1 or />1 is usually compos$ ( six triangles1 ! apexes ( :i* are elevat$ & jo9$ toge!r1 =m+ "o po9t 9 ! c5tre4 ,f _! bases desc5d a fur!r s]ies ( triangles1 ! bases & apexes ( :i* are =m$ by ! bases & l[] angles ( ! upp] s]ies4 ,?is l[] belt is call$ ! tee?1 "u :i* ! surface or base ( ! /one is usually flat1 b sometimes p>takes ( a simil> %ape to ! upp] surface1 ?\gh some:at modifi$ 9 =m4 ,ano!r v>iety is call$ ! table cut1 & is us$ = col\r$ /ones4 ,x has a flat top or table ( a squ>e or o!r %ape1 ! edges ( :i* slope outw>ds & =m ! bezils or t ext5d$ portion by :i* ! /one is held 9 its sett+4 ,x w ?us be se5 t ! outside ( ! /one is ( ! same %ape z t ( ! table1 b l>g]1 s t f e portion ( ! table ! surface ext5ds d[nw>ds1 slop+ outw>ds to ! extreme size ( ! /one1 ! und]side slop+ d[nw>ds & inw>ds to a small & flat base1 ! :ole1 9 section1 be+ n unlike ! section ( a pegtop4 ,a modification ( ?is is kn[n z ! /ep cut1 sometimes also call$ ! trap4 ,briefly1 ! diff]5ce betwe5 ?is & ! la/ is t :]eas ! table has usually "o bevel on ! upp] & l[] surfaces1 ! trap has "o or m /eps 9 ! slop+ p>ts1 h5ce its "n4 ,! mo/ common ( all1 & usually appli$ only to ! diamond1 is ! brilliant cut4 ,?is is some:at complicat$1 & requires detail$ description4 ,9 section1 ! %ape is sub/antially t ( a pegtop ) a flat table top & a small flat base4 ,! wide/ portion is t on :i* ! claws1 or o!r =m ( sett+1 hold x securely 9 position4 ,?is portion is call$ ! girdle1 & if we take ?is z a def9+ l9e1 t portion :i* appe>s above ! sett+ ( ?is girdle1 is call$ ! cr[n2 ! portion bel[ ! girdle is call$ ! culasse1 or less commonly ! pavilion4 ,comm5c+ ) ! girdle upw>ds1 we h eight cross facets 9 f\r pairs1 a pair on ea* side2 ea* pair hav+ _! apexes toge!r1 meet+ on ! f\r extremities ( two l9es drawn lat]ally at "r angles ?r\gh ! /one4 ,x w1 !re=e1 be se5 t "o side ( ea* triangle co9cides ) ! girdle1 & z _! bases d n meet1 ^! spaces are occupi$ by eight small triangles1 call$ skill facets1 ea* ( :i* has1 z its base1 ! girdle1 & ! out] ( its sides co9cides ) ! base ( ! adjo9+ cross facet4 ,! two inn] sides ( ea* pair ( skill facets =m ! half ( a diamond or loz5ge-%ap$ facet1 call$ a quo91 ( :i* !re are f\r4 ,! inn] or upp] half ( ea* ( ^! f\r quo9s =ms ! bases ( two triangles1 "o at ea* side1 mak+ eight 9 all1 :i* are call$ /> facets1 & ! inn] l9es ( ^! eight /> facets =m ! b\nd>y ( ! top ( ! /one1 call$ ! table4 ,! inn] l9es also ( ! /> facets imm$iately bel[ ! table & ^? ( ! cross facets imm$iately above ! girdle =m f\r templets1 or bezils4 ,we ?us h above ! girdle1 ?irty-?ree facets3 #h cross1 #h skill1 #d quo91 #h />1 #a table1 & #d templets4 ,rev]s+ ! /one & aga9 comm5c+ at ! girdle1 we h eight skill facets1 sometimes call$ ! l[] skill facets1 ! bases ( :i* are on ! girdle1 _! out] sides =m+ ! bases ( eight cross facets1 ! apexes ( :i* meet on ! extremities ( ! horizontal l9e1 z 9 ^? above ! girdle4 ,if ! basal l9es ( ^! cross facets1 :]e !y jo9 ! sides ( ! skill facets1 are ext5d$ to ! peak1 or n>r[ end ( ! /one1 ^! l9es1 toge!r ) ! sides ( ! cross facets1 w =m f\r five-sid$ facets1 call$ ! pavilions2 ! spaces betwe5 ^! f\r pavilions h _! ends ne>e/ ! girdle =m$ by ! inn] sides ( ! skill facets1 & ( ^! spaces1 !re w1 ( c\rse1 be f\r1 :i* also are five-sid$ figures1 & are call$ quo9s1 s t !re are eight five-sid$ facets--f\r l>ge & f\r n>r[--_! bases =m+ a squ>e1 ) a small portion ( ea* corn] cut away2 ! bases ( ! broad] pavilions =m ! f\r sides1 :il/ ! bases ( ! f\r n>r[] quo9s cut (f ! corn]s ( ! squ>e1 & ?is flat portion1 b\nd$ by ! eight bases1 is call$ ! culet1 b m commonly collet4 ,s t bel[ ! girdle1 we f9d tw5ty-five facets3 #h cross1 #h skill1 #d pavilion1 #d quo91 & #a collet4 ,^!1 ) ! #cc ( ! cr[n1 make #eh1 :i* is ! usual numb] ( facets 9 a brilliant1 ?\gh ?is v>ies ) ! "*1 quality1 & size ( ! diamond4 ,= in/ance1 ?\gh ?is numb] is consid]$ ! be/ = normal /ones1 specially l>ge ones (t5 h m1 o!rwise !re is dang] ( _! appe>+ dull1 & x requires a va/ am\nt ( skill & exp]i5ce to decide ^u ! p>ticul> numb] & size ( ! facets t w be/ display ! fire & brilliance ( a l>ge /one1 = x is obvi\s t if1 aft] mon?s ( cutt+ & poli%+1 x is f\nd t a great] or small] numb] ( facets ought to h be5 all[$1 ! error _c be retriev$ )\t consid]able loss1 & probable ru9 to ! /one4 ,9 ! case ( ! ,cull9an diamonds1 ! two l>ge/ ( :i* are call$ ! ,/>s ( ,africa1 #gd facets 7 cut 9 ! l>ge/ portion1 :ile 9 ! next l>ge/ ! exp]ts decid$ to make #ff1 &1 z already po9t$ out1 ^! /ones are1 up to ! pres5t "t1 ! mo/ magnific5t 9 fire1 beauty & purity ev] discov]$4 ,! positions & angles ( ! facets1 z well z ! numb]1 are ( supreme importance1 & diamond cutt]s--ev5 ?\gh !y h rules regulat+ ^! matt]s1 accord+ to ! weight & size ( ! /one--mu/ ex]cise ! greate/ c>e & exactitude1 = _! decision once made is practically unalt]able4 ,,*apt] ,,xii4 ,,imitations1 ,,& ,,"s ,,( ,,! ,,te/s1 ,,( ,,preci\s ,,/ones4 ,we n[ arrive at ! po9t :]e x is necess>y to discuss ! manufacture & re-=mation ( preci\s /ones1 & also to consid] a few ( ! te/s :i* may be appli$ to all /ones4 ,^! are giv5 "h 9 ord] to save ne$less repetition2 ! te/s :i* are specially applicable to individual /ones w m prop]ly be f\nd "u ! description ( ! /one ref]r$ to1 s t ! pres5t *apt] w be devot$ *iefly to g5]alities4 ,) reg>d to diamonds1 ! manufacture ( ^! has n z yet be5 v successful4 ,z w be se5 on ref]5ce to ,*apt] ,,ii41 on ! ,orig9 ( ,preci\s ,/ones1 x is g5]ally admitt$ t ^! beautiful & valuable m9]als are caus$ by *emically-*>g$ wat] & occasionally1 ?\gh n always1 high temp]ature1 b inv>iably beautifi$ & br\ght to ! condition 9 :i* !y are obta9$ by ! action ( weight & pressure1 ext5d+ unbrok5 ?r\gh p]haps ages ( "t4 ,9 ^! circum/ances1 sci5ce1 ?\gh able to give *emical prop]ties & pressure1 _c1 ( c\rse1 ma9ta9 ^! cont9u\sly = ages1 !re=e ! *emi/ mu/ manufacture ! jewels 9 su* mann] t he may soon see ! results ( 8 lab\rs1 & ?\gh real diamonds may be made1 & ) comp>ative ease1 f boron 9 ! amorph\s or pure /ate along ) alum9ium1 fus$ 9 a crucible at a high temp]ature1 ^! diamonds are b microscopic1 nor c a numb] ( !m be fus$1 or 9 any o!r way conv]t$ into a l>ge s+le /one1 s t imitation /ones1 to be ( any s]vice mu/ be made ( a good cle> glass4 ,! glass = ?is purpose is usually compos$ ( #ec4gj p] c5t4 ( r$ lead1 #ch4dh p] c5t4 ( pure qu>tz 9 f9e p[d]1 pref]ably wat]-gr\nd1 & #g4hb p] c5t4 ( c>bonate ( pota%1 ! :ole col\r$ :5 necess>y ) metallic oxides ( a simil> nature to ! con/itu5ts ( ! natural /ones imitat$4 ,b = col\rless diamonds1 ! glass requires no su* addition to t9t x4 ,f ! =mula giv5 is made ! mat]ial kn[n z /rass1 or pa/e1 & /ones made ( x are mo/ly exhibit$ "u & among/ brilliant artificial lights4 ,! m]e fact t !y are sold *eaply is prima facie pro( t ! /ones are glass1 = x is evid5t t a diamond1 ! comm]cial value ( :i* might be ,l#ej or m1 _c be pur*as$ = a few %ill+s & be g5u9e4 ,s long z ?is is und]/ood & ! /one is sold = ! few %ill+s1 no h>m is done2 b to (f] x z a g5u9e /one & at ! price ( a g5u9e /one1 w\ld am\nt to fraud1 & be puni%able accord+ly4 ,"s ( ^! pa/e1 or :ite /ones1 z !y are call$ 9 ! trade1 are cut & poli%$ exactly l a diamond1 & ) su* success z occasionally to deceive all b exp]ts4 ,su* imitations are co/ly1 ?\gh1 ( c\rse1 n approa*+ ! value ( ! real /ones2 x be+ no uncommon ?+ = valuable jewels to be duplicat$ 9 pa/e1 :il/ ! orig9als are kept 9 ! /rong room ( a bank or safe-deposit4 ,9 all cases1 h[ev]1 a h>d file w abrade ! surface ( ! false /one4 ,9 *apt] ,,vii4 we f\nd t qu>tz is 9 ! sev5? degree ( h>dness1 & an ord9>y file is b a %ade h>d] ?an ?is1 s t almo/ all /ones high] ?an ,no4 #g are unaffect$ by a file unless x is us$ r\ghly1 s z to break a %>p edge4 ,9 ord] to prep>e artificial diamonds & o!r /ones = ! file & v>i\s te/s1 !y are (t5 :at is call$ conv]t$ into d\blets or triplets4 ,^! are made z foll[s3 ! body ( ! glass is ( pa/e1 & on ! table 7see la/ *apt]71 & p]haps on ! broad] facets1 !re w be plac$ a v ?9 slab ( ! real /one1 atta*$ by cem5t4 ,9 ! case ( ! diamond1 ! body is cle>1 b 9 ! col\r$ imitations ! pa/e portion is made some:at light] 9 %ade ?an ! real /one w\ld be1 ! portion bel[ ! girdle be+ col\r$ *emically1 or m\nt$ 9 a col\r$ back+4 ,su* a /one w1 ( c\rse1 /& mo/ te/s1 = ! p>ts usually te/$ are g5u9e4 ,a /one ( ?is nature is call$ a d\blet1 & x is evid5t t :5 x is te/$ on ! und]side1 x w prove too s(t1 !re=e ! triplet has be5 introduc$4 ,?is is exactly on ! l9es ( ! d\blet1 except t ! collet & p]haps ! pavilions are cov]$ also1 s t ! girdle1 :i* is g5]ally encas$ by ! m\nt+1 is ! only surface-portion ( pa/e4 ,9 o!r cases ! :ole ( ! cr[n is g5u9e1 :il/ (t5 bo? ! upp] & l[] portions are solid & g5u9e1 ! sav+ be+ effect$ by us+ a pa/e c5tre at ! girdle1 cov]$ by ! m\nt+4 ,su* a /one z ?is la/ m5tion$ is (t5 difficult to detect )\t us+ sev]e te/s & desp]ate means1 e4g43--7a7 by its cry/all9e /ructure 7see ,*apt] ,,iii472 7b7 by ! cleavage planes 7see ,*apt] ,,iv472 7c7 by ! pol>iscope 7see ,*apt] ,v472 7d7 by ! di*roscope 7see ,*apt] ,,vi472 7e7 by specific gravity 7see ,*apt] ,,viii472 7f7 cutt+ (f ! m\nt+1 & exam9+ ! girdle2 7g7 soak+ ! /one = a m9ute or s 9 a mixture said to h be5 orig9ally discov]$ by ,m4 ,d4 ,ro?s*ild1 & compos$ ( hydr(luoric acid & ammonia2 ?is w n answ] = all /ones1 b is safe to use = ! diamond & a few o!rs4 ,%\ld ! jewel be glass1 x w be et*$1 if n completely de/roy$1 b if g5u9e1 no *ange w be app>5t2 7h7 soak+ ! diamond = a few m9utes 9 w>m or cold wat]1 9 alcohol1 9 *lor(orm1 or 9 all ^! 9 turn1 :51 if a d\blet1 or triplet1 x w tumble to pieces :]e jo9$ toge!r by ! cem5t1 :i* w h be5 dissolv$4 ,x is1 h[ev]1 seldom necess>y to te/ s f>1 = an exam9ation "u ! microscope1 ev5 ) l[ p[]1 is usually suffici5t to detect 9 ! glass ! air-bubbles :i* are almo/ insep>able f glass-mixtures1 ?\gh !y d n detract f ! physical prop]ties ( ! glass4 ,! high] p[]s ( ! same in/rum5t w almo/ always def9e ! junction & ! lay] or lay]s ( cem5t1 no matt] h[ delicate a film may h be5 us$4 ,any "o ( ^! te/s is suffici5t to isolate a false /one4 ,"s ( ! s(t] g5u9e /ones may be fus$ toge!r ) spl9t]s1 du/1 & cutt+s ( ! same /ones1 & ( ?is product is =m$ a l>g] /one1 :i*1 ?\gh manufactur$1 is ess5tially p]fectly real1 possess+ exactly ! same prop]ties z a naturally =m$ /one4 ,_m su* /ones are obta9$ z l>ge z an ord9>y p9's head1 & are mu* us$ comm]cially = clu/]-"w 9 r+s1 broo*es1 = wat*-jewels1 sc>f-p9s1 & ! l1 & are capable ( be+ cut & poli%$ exactly l an orig9al /one4 ,?is is a means ( us+ up to great advantage ! lapid>y's du/1 & ?\gh ^! products are real /ones1 p]haps a little m enri*$ 9 col\r *emically1 !y are mu* *eap] ?an a natural /one ( ! same size & weight4 ,"s spuri\s /ones h _! col\r improv$ by heat1 by be+ t+$ on ! outside1 by be+ t9t$ ?r\gh\t ) a fix$ col\r & plac$ 9 a cle> sett+2 o!rs1 aga91 h a sett+ ( a diff]5t hue1 s t ! reflection ( ?is %all give additional col\r & fire to ! /one4 ,= in/ance1 glass diamonds are (t5 set ) ! :ole ( ! portion bel[ ! girdle hidd51 ?is "p ( ! /one be+ silv]$ l a mirror4 ,o!rs are set op51 be+ held at ! girdle only1 ! portion cov]$ by ! sett+ be+ silv]$4 ,o!r glass imitations1 su* z ! opal1 h a tol]ably good repres5tation ( ! fi]y opal giv5 to !m by ! admixture1 9 ! glass1 ( a little oxide ( t91 :i* makes x some:at opalesc5t1 & 9 ! sett+ is plac$ a back+ ( r$1 gold1 copp]1 or fi]y-col\r$ t9sel1 :il/ ! glass itself1 at ! back1 is pa9t$ v ?9ly ) a pa9t compos$ ( well wa%$ & dri$ fi%-scales1 r$uc$ to an impalpable p[d]1 mix$ ) a little pure1 ref9$ ma/ic1 or o!r col\rless v>ni%4 ,?is gives a good imitation ( phosphoresc5ce1 z well z a slight pe>l9ess1 :il/ ! t9sel1 se5 ?r\gh ! pa9t & ! curi\s milk9ess ( ! glass1 gives good fire4 ,a k ( ! col\rs natural to preci\s /ones & to jewels g5]ally is ( great s]vice 9 _! r\gh classification = te/+1 ev5 ?\gh "s /ones are f\nd 9 a v>iety ( col\rs4 ,an alphabetical li/ ( ! mo/ useful is "h app5d$1 toge!r ) _! av]age specific gravities & h>dness4 7,see also ,*apt] ,,vii4 on ,h>dness1 & ,*apt] ,,viii4 on ,specific ,gravity47 ,,:ite ,,or ,,col\rless ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,b]yl #g-c_/d #b4gji-b4ha ,corundum #i #c4ij-d4af ,diamond #aj #c4ejb-c4efd ,jade #g #c4cjj-c4cha ,opal #e-a_/b-f-a_/b #b4afj-b4bhc ,ph5akite #g-c_/d #b4ife ,qu>tz #g #b4fgj ,rock-cry/al #g #b4eba-b4gie ,sapphire #i #d4jdi-d4jfj ,sp9el #h #c4fad-c4fed ,topaz #h #c4ejj-c4ebj ,t\rmal9e #g-a_/d #c4jbi ,zircon #g-a_/b #d4gjj-d4hhj ,,yell[ ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,amb] #b-a_/b #a4jjj ,b]yl #g-c_/d #b4gji-b4haj ,*rysob]yl #h-a_/b #c4fhi-c4geb ,*rysolite #f-g #c4caf-c4ebh ,corundum 7! yell[ v>iety kn[n z ,ori5tal ,topaz n ,topaz1 see bel[7 #i #c4ij-d4af ,diamond #aj #c4ejb-c4efd ,g>nets 7v>i\s7 #f-a_/b-g-a_/b #c4d-d4e ,hyac9? 7a =m ( ,zircon7 #g-a_/b #d4g-d4hh ,qu>tz 7,citr9e7 #g #b4feh ,sapphire #i #d4jdi-d4jfj ,sp9el #h #c4fad-c4fed ,topaz 7= ,ori5tal ,topaz1 see above7 #h #c4ejj-c4ebj ,t\rmal9e #g-a_/d #c4baj ,,br[n ,,& ,,flame-,,col\r$ ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,&alusite #g-a_/b #c4bjd ,diamond #aj #c4ejb-c4efd ,g>nets 7v>i\s7 #f-a_/b-g-a_/b #c4dj-d4ej ,hyac9? 7a =m ( ,zircon71 see bel[ #g-a_/b #d4gj-d4hh ,qu>tz 7smoke col\r$7 #g #b4fgj ,t\rmal9e #g-a_/d #c4ajj ,zircon 7,hyac9?7 #g-a_/b #d4gj-d4hh ,,r$ ,,& ,,rose-,,col\r$ ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,c>nelian 7a v>iety ( ,*alc$ony7 #f-a_/b #b4eih-b4faj ,diamond #aj #c4ejb-c4efd ,deep ,r$ ,g>net #g-a_/d #c4dj-d4ej ,jasp] #g #b4ffh ,opal 7! ,fire ,opal7 #e-a_/b-f-a_/b #b4ba 7av]age7 ,ruby #i #d4jgc-d4jhj ,rhodonite #e-a_/b-f-a_/b #c4dac-c4fag ,sapphire #i #d4jdi-d4jfj ,sp9el ,ruby #h #c4fad-c4fed ,topaz #h #c4ejj-c4ebj ,t\rmal9e #g-a_/d #c4jbd ,zircon #g-a_/b #d4gj-d4hh ,,p9k ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,b]yl #g-c_/d #b4gji-b4haj ,diamond #aj #c4ejb-c4efd ,ruby #i #d4jgc-d4jhj ,sp9el #h #c4fad-c4fed ,topaz 7burnt or p9k$71 see ,*apt] ,,xiv41 page #ib #h #c4ejj-c4ebj ,t\rmal9e #g-a_/d #c4jbd ,,blue ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,b]yl #g-c_/d #b4gji-b4haj ,diamond #aj #c4ejb-c4efd ,di*orite 7,wat] ,sapphire7 #g-g-a_/b #d4jdi-d4jfj ,di/h5e 7,kyanite7 #e-g #c4fji-c4fhh ,iolite 7,cordi]ite7 #g-a_/d #b4fda ,lapis lazuli #e-a_/b #b4dfa ,sapphire #i #d4jdi-d4jfj ,topaz #h #c4ejj-c4ebj ,t\rmal9e #g-a_/d #c4afj ,turquoise #f #b4hjj ,,gre5 ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,aquam>9e #g-c_/d #b4gja-b4hjj ,*rysob]yl #h-a_/b #c4fhi-c4geb ,*rysolite #f-g #c4caf-c4ebh ,*rysoprase 7,qu>tz7 #g #b4fgj ,diamond #aj #c4ejb-c4efd ,dioptase #e #c4bhi ,em]ald & ,ori5tal ,em]ald #g-c_/d #b4fij ,euclase #g-a_/b #c4jij ,g>net 7see also ,r$ ,g>net7 #f-a_/b-g-a_/b #c4djj-d4ejj ,heliotrope 7,*alc$ony7 #f-a_/b #b4eih-b4faj ,hidd5ite 7a v>iety ( ,spodum5e7 #f-a_/b-g #c4acj-c4bjj ,jade #g #c4cjj-c4cha ,jadeite #g #c4bii ,mala*ite #c-a_/b #c4gaj-c4iif ,p]idot 7a v>iety ( ,*rysolite7 #f-g #c4caf-c4ebh ,plasma 7a v>iety ( ,*alc$ony7 #f-a_/b #b4eih-b4faj ,qu>tz #g #b4fgj ,sapphire #i #d4jdi-d4jfj ,topaz #h #c4ejj-c4ebj ,t\rmal9e #g-a_/d #c4adh ,,violet ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,ame?y/ #g #b4ffa ,diamond #aj #c4ejb-c4efd ,qu>tz 7,ame?y/7 #g #b4fgj ,sapphire #i #d4jdi-d4jfj ,sp9el #h #c4fad-c4fed ,t\rmal9e #g-a_/d #c4afj ,,*atoyant ,,/ones4 ,^! /ones are easily recognisable by _! play ( col\r4 7,see ,*apt] ,,xiv47 ,,black ,,/ones4 ,h>dness4 ,specific ,gravity4 7,see ,*apt] ,,vii47 7,see ,*apt] ,,viii47 ,diamond #aj #c4ejb-c4efd ,g>net #f-a_/b-g-a_/b #c4djj-d4ejj ,jet #c-a_/b #a4cdh ,onyx 7a v>iety ( ,*alc$ony7 #f-a_/b #b4eih-b4faj ,qu>tz #g #b4fgj ,t\rmal9e 7n unlike ,black ,res9 9 appe>ance7 #g-a_/d #c4jbd-c4cjj ,,*apt] ,,xiii4 ,,v>i\s ,,preci\s ,,/ones4 ,! ,diamond4 ,to recapitulate c]ta9 ( ! facts respect+ ! diamond4--,?is wond]ful gem has ! di/9ction among/ preci\s /ones ( be+ unique2 ?\gh _m are compos$ ( two1 ?ree1 or b a small numb] ( elem5ts1 ! diamond is ! only /one kn[n consi/+ ( "o elem5t1 & absolutely no?+ else--pure cry/allis$ c>bon4 ,its h>dness is prov]bial2 n only is x unt\*$ by ! action ( a h>d file1 b x occasionally refuses to split :5 /ruck ) f9ely temp]$ /eel1 :i* x (t5 causes to break4 ,su* 0 ! case ) ! ,s\? ,african diamond1 = :5 ! knife t 0 to break x 0 /ruck sm>tly ) a /eel b>1 ! fir/ bl[ broke ! blade )\t affect+ ! diamond1 yet a piece ( bort1 or diamond du/1 spl9t]s1 or defective diamonds 7all ^! be+ call$ bort71 may readily be pulv]is$ 9 a h>d /eel mort> ) a h>d /eel pe/le4 ,! diamond is ! h>de/ /one kn[n2 x is also ! only /one kn[n :i* is really combu/ible4 ,x is ( true adamant9e lu/re1 class$ by exp]ts z midway betwe5 ! truly metallic & ! purely res9\s4 ,9 refractive p[] & disp]sion ( ! col\r$ rays ( light1 call$ its fire1 x /&s pre-em95t4 ,x possesses a consid]able v>iety ( col\r2 t reg>d$ z ! mo/ p]fect & r>e is ! blue-:ite col\r4 ,mo/ commonly1 h[ev]1 ! col\rs are cle>1 ) /eely-blue ca/s1 pale & neutral-col\r yell[1 :il/ among/ ! mo/ exp5sive & r>e are ^? ( gre51 pale p9k1 r$1 & any o!r v>iety ) /rong & decid$ col\r4 ,al?\gh ^! /ones are sold by ! c>at1 !re c be no h>d & fa/ rule laid d[n z to ! value ( a c>at1 = ?is dep5ds on ! size1 quality1 & ! purity ( ! /one4 ,! l>g] ! /one ! great] ! value p] c>at1 & prices h be5 kn[n to range f #bel4 p] c>at = a small /one to #ejjl4 p] c>at = a l>ge "o1 :]eas ! exceptionally l>ge /ones possess a value almo/ beyond e/imation4 ,x (t5 happ5s t "s /ones--p>ticul>ly ^? f ,s\? ,africa & ,brazil--are t9t$ :5 uncut1 probably by reason ( ! action ^u !m ( _! matrix1 especially if iron/one1 or ) roll+ = ages among/ iron/one 9 riv]-b$s1 :i* gives !m a slight metallic appe>ance2 9 ea* case ! cause is sugge/$ by ! fact t ^! t9t$ /ones are usually f\nd 9 su* places1 & t ! t9t+ is v ?9 & on ! surface only1 s t ! cutt+ & %ap+ ( ! /one gets bel[ x to ! p]fectly cle> diamond4 ,f ,pl9y & o!r hi/orians we ga!r t at v>i\s p]iods consid]able sup]/ition has exi/$ ) reg>d to diamonds1 su* z t if "o is p[d]$ x becomes poison\s to a rem>kable degree2 t gifts ( diamonds betwe5 lov]s--m>ri$ & unm>ri$--produce & seal affection2 h5ce ! popul>ity ( diamonds 9 betro?al r+s4 ,pretty z is ?is conceit1 !re is no d\bt ab\t ! fact t ! gift ( diamonds to ! object ( "o's affections does usually produce a feel+ ( pleasure to bo? p>ties1 f :i* x w\ld appe> t !re is "s gr\nd = ! belief4 ,corundum4 ,?is m9]al is a species ( cry/al1 or cry/all9e alum9a--an almo/ pure anhydr\s alum9a1 ,al#b,o#c--;9 _m v>ieties1 bo? ( %ape & col\r4 ,! *ief /one is ! ruby1 consid]$1 :5 l>ge1 to be ( ev5 m importance & value ?an ! diamond4 ,!re are _m o!r r$ /ones 9 ?is gr\p2 sapphires1 also1 are a species ( corundum1 bo? ! blue & ! col\rless v>ieties1 z are also ! aquam>9e1 ! em]ald1 ! ame?y/1 ! topaz1 & o!rs1 all ( widely diff]+ col\r1 z well z ! />-%ap$1 or a/] ruby1 call$ ! ruby cat's-eye4 ,all ^! v>y m 9 col\r ?an 9 _! *emical prop]ties4 ,/ill ano!r v>iety1 greyi%-black & g5]ally associat$ ) haematite iron ore1 is call$ em]y1 &1 :5 gr\nd 9 diff]5t degrees ( f95ess1 is s well kn[n by its g5]al use z a poli%+ m$ium z to ne$ no description4 ,x %\ld1 h[ev]1 be m5tion$ t among/ ! m co>sely gr\nd em]y x is no uncommon ?+ to f9d m9ute sapphires1 tak+ sapphires 9 _! broad1 comm]cial mean+1 z signify+ any v>iety ( corundum1 except ! r$ & ! em]y4 ,! surfaces ( cry/als ( corundum are (t5 cl\d$ or dull1 :il/ its classification ( lu/re is vitre\s4 ,x is d\ble refract+ & has no cleavage4 ,x is f\nd 9 ,*9a1 ,india1 ,burma1 ,ceylon1 ,s\? ,africa1 ,am]ica1 & 9 _m o!r places1 hav+ a wide di/ribution4 ,! ,ruby4 ,9 ! di*roscope ! ruby %[s two images1 "o squ>e ( a violet r$1 ! second squ>e be+ a tru] & a pal] r$4 ,x may be subject$ to /rong heat1 :5 x *anges its col\r to a sooty or dirty slate1 ?is v>y+ ) ! locality 9 :i* ! /one is f\nd1 & ! mann] 9 :i* ! heat is appli$4 ,b z x cools x becomes pal] & gre5]1 till x sl[ly enri*5s2 ! gre5 fir/ becomes brok51 !n w>m]1 r$d]1 & f9ally assumes its orig9al beautiful blood r$4 ,?is me?od ( heat+ is sometimes us$ z a te/1 b x is a te/ :i* (t5 means ! complete ru9 ( a /one :i* is n g5u9e4 ,ano!r *>act]i/ic :i*1 9 ! eyes ( ! exp]t1 inv>iably isolates a real f an artificial ruby is its curi\s mild brilliance1 :i* z yet has n be5 reproduc$ by any sci5tific me?od 9 pa/e or any o!r mat]ial1 b p]haps ! safe/ te/ ( all is ! cry/all9e /ructure1 :i* id5tical /ructure appe>s 9 no o!r /one1 ?\gh x is possible1 by heat+ alum9a col\r$ ) oxide ( iron & p]haps also a trace ( oxide ( *romium to a v high temp]ature = a consid]able "t1 & !n cool+ v sl[ly1 to obta9 a ruby :i* is ne>ly ! same 9 its /ructure z ! real gem2 its specific gravity & h>dness may p]haps be to /&>d1 & :5 prop]ly cut1 its brilliance w\ld deceive all b an exp]t4 ,& z 9 "s real rubies !re are f\nd slight holl[s correspond+ or analog\s to ! bubbles f\nd 9 melt$ glass1 x becomes a matt] ( great difficulty to di/+ui% ! real f ! imitation by su* te/s z h>dness1 specific gravity1 di*roism1 & ! l1 s t 9 su* a case1 %ort ( risk+ ! ru9 ( ! /one1 ord9>y p]sons are unable to apply any conv9c+ te/s4 ,!re=e1 only ! exp]t c decide1 by 8 appreciation ( ! delicate %ade ( diff]5ce 9 ! light ( a true ruby & t ( an excell5t imitation1 & by ! di/ribution ( ! col\r1 :i*--h[ev] exp]i5c$ ! *emi/ may be1 or ) :at c>e ! col\r+ matt] may h be5 incorporat$ 9 ! mass--has be5 f\nd impossible ( di/ribution ?r\gh\t ! body ( an artificial /one s p]fectly & 9 ! same mann] & direction z nature h]self di/ributes x 9 ! g5u9e4 ,?is alone1 ev5 9 ! close/ imitations1 is cle> to ! eye ( ! exp]t1 ?\gh n to ! untra9$ eye1 unless ! /one is palpably spuri\s4 ,to "o :o is accu/om$ to ! exam9ation ( preci\s /ones1 h[ev] p]fect ! imitation1 x is b necess>y to place x beside or among/ "o or m real ones = ! false to be almo/ in/antly id5tifi$1 & t ) c]ta9ty4 ,! ,sapphire4 ,! ,sapphire is n s easy to imitate1 z its h>dness exce$s t ( ! ruby1 & imitations conta9+ its kn[n con/itu5ts1 or ( glass1 are inv>iably s(t] ?an ! natural /one4 ,z be=e rem>k$1 almo/ any =m ( corundum o!r ?an r$ is1 broadly1 call$ sapphire1 b giv+ !m _! /rictly correct designations1 we h ! oliv9e corundum1 call$ *rysolite 7ori5tal71 :i* is h>d] ?an ! ord9>y or noble *rysolite1 sometimes call$ ! p]idot4 ,! v>i\s yell[ v>ieties ( corundum take ! "n ( ! ori5tal topaz1 :i*1 l mo/1 if n all1 ! corundum v>ieties1 is h>d] ?an ! gem :i* be>s ! same "n1 m9us ! prefix ori5tal4 ,!n we h ! ame?y/ sapphire1 :i* v>ies f a r$ to a blue purple1 be+ ri*] 9 col\r ?an ! ord9>y ame?y/1 :i* is a =m ( violet-col\r$ qu>tz1 b ! corundum v>iety1 :i*1 l its companions1 is call$ ! ori5tal ame?y/1 is bo? r>] & m preci\s4 ,a v r>e & extremely beautiful gre5 v>iety is call$ ! ori5tal em]ald4 ,! ori5tal jac9?1 or hyac9?1 is a br[n-r$ corundum1 :i* is m /able ?an ! ord9>y hyac9?1 ?is latt] be+ a =m ( zircon2 x *anges col\r on exposure to light1 :i* col\r is n re/or$ by subsequ5t ret5tion 9 d>kness4 ,! blue sapphire is ( all %ades ( blue1 f cornfl[] blue to ! v pale/ t9ts ( ?is col\r1 all ! gradations f light to d>k purple blues1 &1 9 fact1 s _m %ades ( tone & col\r t !y become almo/ z num]\s z ! /ones4 ,^! /ones are usually f\nd 9 simil> situations to ^? :i* produce ! ruby1 & (t5 along ) !m4 ,! light] col\rs are usually call$ females1 or fem99e /ones1 :il/ ! d>k] ones are call$ mascul9e /ones4 ,"s ( ^! d>k ones are s deep z to be almo/ black1 :5 !y are call$ ink sapphires1 & if incl9+ to blue1 indigo sapphires1 9 contradi/9ction to :i* ! pale/ ( ! /ones are call$ wat] sapphires4 ,! col\r+ matt] is n always ev51 b is (t5 spread ov] ! sub/ance ( ! /one 9 scabs or splot*es1 :i* r fav\rs imitation1 &1 :]e ?is unev5ness occurs1 x may be necess>y to cut or divide ! /one1 or s to arrange ! =m ( x t ! f9i%$ /one %all be equally blue ?r\gh\t4 ,9 "s cases1 h[ev]1 ! sapphire may owe its beauty to ! pres5ce ( two1 ?ree or m col\rs 9 sep>ate /rata appe>+ 9 "o /one2 su* z a portion be+ a gre5-blue1 ano!r a cornfl[] blue1 ano!r p]fectly col\rless1 ano!r a pale sky blue1 ano!r yell[1 ea* p]fectly di/9ct1 ! /one be+ cut s z to %[ ea* col\r 9 its full p]fection4 ,?is /one1 ! sapphire1 is h>dness ,no4 #i 7see ,h>dness table71 & !re=e ranks next to ! diamond1 :i* makes x a matt] ( great difficulty to obta9 an imitation :i* is ( ! same specific gravity & ( ! same degree ( h>dness1 ?\gh ?is has be5 done4 ,su* /ones are pur*asable1 b ?\gh sold z imitations at comp>atively l[ price1 & ! buy] may consid] !m j z good z ! real gem1 to ! exp]i5c$ eye !y are readily detectable4 ,by heat+ a sapphire its blue col\r sl[ly fades1 to complete transp>5cy 9 _m cases1 or at any rate to s pale a t9t z to pass = a transp>5t /one4 ,valuable z is ! sapphire1 ! diamond is m s1 & x foll[s t if "o ( ^! cle> or cle>$ sapphires is cut 9 ! rose or brilliant =m--:i* =ms are res]v$ almo/ exclusively = ! diamond--su* a /one w\ld pass v well z a diamond1 & _m s cut are sold by unscrupul\s p z ! m valuable /one1 :i* fraud an exp]t w\ld1 ( c\rse1 detect4 ,sapphires are m5tion$ by ,pl9y1 & figure l>gely 9 ! anci5t hi/ory ( ,*9a1 ,egypt1 ,rome1 etc4 ,! ,greeks d$icat$ ! sapphire specially to ,jupit]1 & _m ( ! /ones 7 cut to repres5t ! god2 x also figur$ z "o ( ! *ief /ones worn by ! ,jewi% ,high ,prie/ on ! brea/-plate4 ,"s /ones h curi\s rays ( v>iegat$ col\r1 due to _! cry/all9e =mation1 tak+ ! %ape ( a />2 ^! are call$ a/]iat$1 or cat's eye sapphires4 ,o!rs h curi\s fla%es ( light1 te*nically call$ a play ( light 7z describ$ 9 ,*apt] ,,vi4 on ,col\r71 toge!r ) a curi\s blue opalesc5ce2 ^! are ! girasol4 ,ano!r int]e/+ v>iety ( ?is blue sapphire is "o kn[n z *atoyant2 ?is has a rapidly *ang+ lu/re1 :i* seems to undulate betwe5 a gre5-yell[ & a lum9\s blue1 ) a phosphoresc5t gl[1 or fire1 some?+ l t se5 9 ! eyes ( a cat 9 ! d>k1 or ! /eady1 burn+ gl[ obs]v$ :5 ! cat is fasc9at+ a bird--h5ce its "n4 ,?is is n ! same v>iety z ! a/]iat$1 or cat's eye or lynx eye m5tion$ above4 ,,*apt] ,,xiv4 ,,v>i\s ,,preci\s ,,/ones--cont9u$4 ,! ,*rysob]yl4 ,!re are c]ta9 /ones & o!r m9]als :i*1 ow+ to _! possession ( num]\s microscopically f9e cavities1 ( a globul> or tubul> %ape1 h ! appe>ance ( rays or />s1 & ^! are call$ a/]iat$4 ,sev]al ( su* /ones h be5 discuss$ already 9 ! la/ *apt]1 & 9 addition to ^! />-l rays1 "s ( ! /ones h1 runn+ ?r\gh _! sub/ance1 "o or m /reaks1 p]haps ( asbe/os or calcite1 "s be+ p]fectly cle>1 :il/ o!rs are opalesc5t4 ,:5 ^! /reaks pass across ! />-l radiations !y give ! /one ! appe>ance ( an eye1 ! rays =m+ ! iris1 ! cle>1 opalesc5t1 or black /reak closely resembl+ ! slit 9 a cat's eye1 & :5 ^! /ones are cut en cabo*on1 t is1 dome-%ap$ 7see ,*apt] ,,xi4 on ,cutt+71 !re is no?+ to deflect ! light beams back & =? f facet to facet1 z 9 a diamond1 s t ! light1 act+ directly on ^! radiations or masses ( globul> cavities & on ! /reak1 causes ! =m] to gl[ l liv+ fire1 & ! /reak appe>s to vibrate1 palpitate1 exp&1 & contract1 exactly l ! slit 9 ! eye ( a cat4 ,!re are a consid]able numb] ( sup]/itions 9 connection ) ^! cat's-eye /ones1 _m p reg>d+ !m z mascots1 or ) disfav\r1 accord+ to _! col\r4 ,:5 possess+ ! fav\rite hue or fire ( ! we>]1 su* z ! fire ( ! opal = ^? born 9 ,octob]1 ( ! ruby = ^? born 9 ,july1 etc41 ^! /ones are consid]$ to br+ no?+ b good luck2 to w>d (f accid5t1 dang]1 & sudd5 dea?2 to be a *>m aga9/ be+ bitt5 by animals1 & to be a protection f poison1 ! evil eye1 etc4 ,!y figur$ l>gely1 along ) o!r valuable jewels1 9 ! wor%ip ( ! anci5t ,egyptians1 & h be5 f\nd 9 "s ( ! tombs 9 ,egypt4 ,!y also appe>$ on ! sy/rum1 :i* 0 a sacr$ in/rum5t us$ by ! anci5t ,egyptians 9 ! p]=mance ( _! religi\s rites1 p>ticul>ly 9 _! sacrifices to ! goddess ,isis4 ,?is1 !re=e1 may be consid]$ "o ( _! sacr$ /ones1 :il/ !re is "s analogy betwe5 ! cat's-eye /ones & ! sacr$ cat ( ! ,egyptians :i* recurs s (t5 9 _! hi]oglyphics2 x is well kn[n t our dome/ic cat is n desc5d$ f ! wild cat1 b f ! celebrat$ cat ( ,egypt1 :]e hi/ory records its be+ dome/icat$ at lea/ ?irte5 c5turies ,b4,c4 ,f !re x 0 tak5 ?r\gh\t ,europe1 :]e x appe>$ at lea/ a c5tury ,b4,c41 & 0 kept z a pet 9 ! homes ( ! weal?y1 ?\gh c]ta9 writ]s1 speak+ ( ! m\se-hunt]s ( ! old ,romans & ,greeks1 /ate t ^! creatures 7 n ! ,egyptian cat1 b a c>niv]\s1 long-bodi$ animal1 aft] ! %ape ( a weasel1 call$ m>t51 ( ! species ! bee* or common m>t5 7mu/ela fo9a71 f\nd also 9 ,brita9 to-day4 ,x is also int]e/+ to note t ! v>i\s sup]/itions exi/+ ) reg>d to ! diff]5t v>ieties & col\rs ( cats also exi/ 9 an id5tical mann] ) ! correspond+ col\rs ( ! m9]als kn[n z cat's eye4 ,sev]al v>ieties ( cat's-eye h already be5 describ$4 ,ano!r important v>iety is t ( ! *rysob]yl call$ cymophane4 ,?is is compos$ ( gluc9a1 :i* is gluc9um oxide1 or b]yllia1 ,be,o1 ( :i* !re is #ai4h p] c5t41 & alum9a1 or alum9ium oxide1 ,al#b,o#c1 ( :i* !re is #hj4b p] c5t4 ,x has1 !re=e1 ! *emical =mula1 ,be,o1,al#b,o#c4 ,?is /one %[s positive electricity :5 rubb$1 &1 unlike ! sapphires describ$ 9 ! la/ *apt]1 :i* lose _! col\r :5 heat$1 ?is v>iety ( *rysob]yl %[s no *ange 9 col\r1 & any electricity giv5 to x1 ei!r by friction or heat1 is reta9$ = a long "t4 ,:5 heat$ 9 ! bl[pipe alone x rema9s unalt]$1 t is1 x is n fusible1 & ev5 ) microcosmic salt x requires a consid]ably long & fi]ce heat be=e x yields & fuses1 & acids d n act ^u x4 ,x cry/allises 9 ! #d? 7rhombic7 sy/em1 & its lu/re is vitre\s4 ,! cymophane %[s a numb] ( v>ieties1 q z _m z ! *rysob]yl1 ( :i* x is itself a v>iety1 & ^! g ?r\gh ! gamut ( gre5s1 f a pale :ite gre5 to ! /rong] gre5 ( asp>agus1 & ?r\gh bo? ! grey & yell[ gre5s to d>k4 ,x is f\nd 9 ,ceylon1 ,moravia1 ! ,ural ,m\nta9s1 ,brazil1 ,nor? ,am]ica1 & else:]e4 ,! cat's-eye ( ?is is v simil> to ! qu>tz cat's-eye1 b a comp>ison w make ! diff]5ce s cle> t !y c\ld nev] be mi/ak51 ap>t f ! fact t ! qu>tz has a specific gravity consid]ably l[] ?an ! *rysob]yl cat's-eye1 :i* latt] is ! true cat's-eye1 & ! "o usually und]/ood :5 allusion is made to ! /one )\t any di/+ui%+ prefix1 su* z ! ruby1 sapphire1 qu>tz1 etc41 cat's eye4 ,x %\ld1 h[ev]1 be m5tion$ t ?is /one is ref]r$ to :5 ! names ,ceylonese & ,ori5tal cat's-eye are giv51 :i* names are us$ 9 ! trade z well z ! simple appellation1 cat's eye4 ,"o peculi>ity ( "s ( ^! /ones is t ! fire or gl[ is usually alt]$ 9 col\r by ! col\r ( ! light "u :i* x is se51 ! *ange ( col\r be+ g5]ally ! complem5t>y4 ,?us1 a /one :i* 9 "o light %[s r$1 9 ano!r w be gre52 ! eye %[+ blue 9 "o light w become orange 9 ano!r2 :il/ ! yell[ ( ano!r /one may %[ a decid$ purple or ame?y/ 9 a diff]5t light4 ,a good te/ = ?is1 & inde$ mo/ preci\s /ones1 is t !y conduct heat m quickly ?an does glass1 & ) su* rapidity t on brea?+ ^u a /one ! w>m? is conduct$ in/antly1 s t1 ?\gh ! /one is dimm$ ! dimness vani%es at once1 :]eas ) glass ! film ( moi/ure fades b sl[ly 9 comp>ison4 ,! ,topaz4 ,! "n topaz is d]iv$ f ! ,greek topazos1 :i* is ! "n ( a small isl& situat$ 9 ! ,gulf ( ,arabia1 f :5ce ! ,romans obta9$ a m9]al :i* !y call$ topazos & topazion1 :i* m9]al to-day is t]m$ *rysolite4 ,! m9]al topaz is f\nd 9 ,cornwall & 9 ! ,briti% ,isles g5]ally2 also 9 ,sib]ia1 ,india1 ,s\? ,am]ica & _m o!r localities1 "s ( ! f9e/ /ones com+ f ,saxony1 ,bohemia1 & ,brazil1 especially ! la/-nam$4 ,! cleavage is p]fect & p>allel to ! basal plane4 ,x cry/allises 9 ! #d? 7rhombic7 sy/em2 9 lu/re x is vitre\s2 x is transp>5t1 or rang+ f t to transluc5t2 ! /reak is :ite or col\rless4 ,its col\r v>ies v mu*--"s /ones are /raw-col\r1 "s are grey1 :ite1 blue1 gre51 & orange4 ,a v fav\rite col\r is ! p9k1 b 9 mo/ cases ?is col\r is n natural to ! /one1 b is ! result ( burn+1 or p9k+ z ! process is call$ te*nically1 :i* process is to raise ! temp]ature ( a yell[ /one till ! yell[ t9t turns to a p9k ( ! col\r desir$4 ,! topaz is h>d] ?an qu>tz1 z w be se5 on ref]5ce to ! ,h>dness table1 & is compos$ ( a silicate ( alum9ium1 fluor9e tak+ ! place ( "s ( ! oxyg54 ,its composition av]ages #af4be p] c5t4 ( silica1 #ee4ge p] c5t4 ( alum9a1 or oxide ( alum9ium1 & fluoride ( silicium1 #bh p] c5t4 ,its =mula is ,al7,f1,,oh7#b ,si,o#d1 or 7,al,f7#b,si,o#d4 ,f ?is x w be und]/ood t ! fluor9e w be evolv$ :5 ! /one is fus$4 ,x is1 h[ev]1 v difficult to fuse1 & alone x is infusible "u ! bl[pipe1 b ) microcosmic salt x fuses & evolves fluor9e1 & ! glass ( ! tube 9 ! op5 end ( :i* ! /one is fix$ is bitt5 ) ! gas4 ,su* exp]im5ts ) ! topaz are highly int]e/+1 & if we take a little ( ! p[d]$ /one & mix ) x a small portion ( ! microcosmic salt1 we may apply ! usual te/ = analys+ & prov+ alum9ium1 ?us3 a /rongly brilliant mass is se5 :5 hot1 & if we moi/5 ! p[d] ) nitrate ( cobalt & heat aga91 ?is "t 9 ! inn] flame1 ! mass becomes blue4 ,o!r ph5om5a are se5 dur+ ! influ5ce ( heat4 ,"s /ones1 z /at$1 become p9k on heat+1 b if ! heat+ is cont9u$ too long1 or too /rongly1 ! /one is decol\r$4 ,o!rs1 aga91 suff] no *ange1 & ?is has l$ to a slight diff]5ce ( op9ion among/ *emi/s z to :e!r ! col\r is due to inorganic or organic matt]4 ,heat+ also produces electricity1 & ! /one1 & ev5 spl9t]s ( x1 w give out a curi\s phosphoresc5t light1 :i* is sometimes yell[1 sometimes blue1 or gre54 ,friction or pressure produces /rong electrification2 ?us ! /ones may be electrifi$ by %ak+ a few toge!r 9 a bag1 or by ! tumbl+ ( ! p[d]$ /one-gra9s ov] ea* o!r z !y roll d[n a %ort incl9$ plane4 ,! /ones are usually f\nd 9 ! primitive rocks1 v>y+ some:at 9 diff]5t localities 9 _! col\r2 _m ( ! ,brazilian /ones1 :5 cut z diamonds1 are n unlike !m4 ,9 te/+1 besides ^? qualities already enum]at$1 ! cry/all9e /ructure is specially p]fect & unmi/akable4 ,x is d\bly refractive1 :]eas sp9el & ! diamond1 :i* two x closely resembles1 are s+ly refractive4 ,topaz is readily electrifi$1 &1 if p]fect at t]m9als1 becomes pol>is$2 also ! comm]cial solution ( violets1 ( :i* a drop only ne$ be tak5 = te/1 is turn$ gre5 by add+ to x a few gra9s ( topaz du/1 or ( a little spl9t] cru%$ to f9e p[d]4 ,! ,b]yl4 ,! b]yl is a comp\nd ( silicates ( b]yllia & alum9a1 ) ! =mula #c;,be,o,si,o#b ,al#b,o#c1c,si,o#b1 or #c;,be,o1,al#b,o#c1f,si,o#b4 ,x diff]s v little inde$ f ! em]ald1 ) ! exception ( its col\r4 ,9 ! ord9>y v>ieties ?is is some:at poor1 be+ mo/ly blue1 or a dirty or a gre5i% yell[2 ! bett] k9ds1 h[ev]1 possess magnific5t col\r & v>iety1 su* z 9 ! aquam>9e1 em]ald1 etc4 ,! cleavage is p>allel to ! basal plane4 ,its lu/re is sometimes res9\s1 sometimes vitre\s1 & x cry/allises 9 ! #bnd 7hexagonal7 sy/em4 ,x occurs 9 some:at long1 hexagonal prisms1 ) smoo?1 truncat$ planes1 & is (t5 f\nd 9 granite & ! silt br\ght d[n by riv]s f granite1 gneiss1 & simil> rocks4 ,x is f\nd 9 ,great ,brita9 & 9 _m p>ts ( ,europe1 ,asia1 & ,am]ica1 9 cry/als ( all sizes1 f small to ! weight ( sev]al tons4 ,! common k9ds are too opaque & col\rless to be us$ z gems & are some:at difficult ( fusion "u ! bl[pipe1 on ! application ( :i* heat "s /ones lose _! col\r altoge!r1 o!rs p>tly2 o!rs1 :i* be=e heat+ 7 some:at transp>5t1 become cl\d$ & opaque2 o!rs suff] no *ange 9 col\r1 :il/ "s are improv$4 ,9 almo/ e case a slight fusion is se5 on ! %>p edges ( fractures1 :i* become smoo?1 lose _! %>pness1 & h ! appe>ance ( p>tly fus$ glass4 ,! h>dness v>ies f #g-a_/d to #h1 ! cry/als be+ v brittle1 break+ ) a fracture ( great unev5ness4 ,! bett] v>ieties are transp>5t1 v>y+ f t to transluc5t1 & are call$ ! noble b]yls4 ,transp>5t b]yl cry/als are us$ by =tune-tell]s z gaz+ /ones1 9 :i* !y claim to see visions ( future ev5ts4 ,! ,em]ald4 ,consid]+ ! p>ticul> em]ald :i* is a v>iety ( b]yl--al?\gh ! "n em]ald 9 ! trade is appli$ some:at loosely to any /one :i* is ( ! same col\r1 or approa*+ ! col\r ( ! b]yl v>iety--?is em]ald only diff]s *emically f ! b]yl1 j describ$1 9 possess+ an addition ( oxide ( *romium4 ,9 %ape1 cry/allisation1 fracture & h>dness1 x is ! same1 & (t5 conta9s1 9 addition to ! *romium1 ! fur!r addition ( traces ( c>bonate ( lime1 magnesia1 & occasionally fa9t traces ( hornbl5de & mica1 :i* evid5tly result f its intimate association ) ! granite rock & gneiss1 among/ :i* x is mo/ly f\nd1 ! latt] rocks be+ ( a slaty nature1 9 lay]s or plates1 &1 l granite1 conta9+ mica1 pyrites1 felsp>1 qu>tz1 etc4 ,em]alds h be5 kn[n f v e>ly times1 & are suppos$ to h be5 f\nd fir/ 9 ! m9es ( anci5t ,egypt4 ,!y 7 consid]$ among/ ! r>e/ & ! mo/ co/ly ( gems1 & x 0 ! cu/om1 :5 conf]r+ lavi% hon\r1 to engrave or model em]alds = pres5tation purposes4 ,?us we f9d ,pl9y describes ,ptolemy giv+ ,lucullus1 on 8 l&+ at ,alex&ria1 an em]ald on :i* 0 engrav$ 8 portrait4 ,pl9y also relates h[ ! %ort-sight$ ,n]o wat*$ ! fights ( gladiators ?r\gh an eye-glass made ( an em]ald1 & 9 anci5t times1 9 ,rome1 ,greece1 & ,egypt1 eye-glasses made ( em]alds 7 mu* valu$4 ,_m ( ^!1 z well z engrav$ & c>v$ em]alds1 h be5 discov]$ 9 ru9s & tombs ( ^? p]iods4 ,! copp] em]ald is r>e2 x is a hydr\s =m ( copp] silicate1 ,cu,o,si,o#b ,h#b,o1 ( a beautiful em]ald gre51 v>y+ f transp>5t to transluc5t4 ,x exhibits d\ble refraction1 & is a cry/allis$ m9]al1 brittle1 & %[+ a gre5 /reak4 ,?is is less h>d ?an ! real em]ald1 is heavi]1 deep] 9 col\r1 & is usually f\nd 9 cry/als1 9 cavities ( a p>ticul> k9d ( lime/one :i* exi/s at ,altyn-,tuebe1 a hill 9 ! ,altai ,m\nta9s1 9 ! ,urals1 & 9 ,nor? & ,c5tral ,am]ica4 ,! ,t\rmal9e4 ,! t\rmal9e is a mo/ complex sub/ance2 almo/ e /one obta9$ has a diff]5t composition1 "s v>y+ b slightly1 ) m]e traces ( c]ta9 con/itu5ts :i* o!r /ones possess 9 a p]ceptible degree4 ,consequ5tly1 x is n possible to give ! *emical =mula1 :i* might1 & possibly w\ld1 be f\nd b seldom1 ev5 9 analyses ( _m specim5s4 ,x w !re=e be suffici5t to /ate ! av]age composition1 :i* is3--f]r\s oxide1 mangan\s oxide1 pota%1 lime1 boracic acid1 magnesia1 soda1 li?ia1 & wat]4 ,^! =m1 r\ghly speak+1 #be p] c5t4 ( ! bulk1 ! rema9d] be+ oxide ( silicon & oxide ( alum9ium 9 ab\t equal p>ts4 ,x cry/allises 9 ! #bnd 7hexagonal7 sy/em1 ) difficult cleavage & vitre\s lu/re4 ,x w naturally be expect$ t a sub/ance ( su* complexity & v>iety ( composition mu/ necess>ily h a correspond+ v>iety ( col\r2 ?us we f9d 9 ?is1 z 9 ! corundum1 a wond]ful range ( t9ts4 ,! common is ! black1 :i* is n us$ z a gem4 ,next come ! col\rless specim5s1 :i* are n (t5 cut & poli%$1 :]eas all ! transp>5t & col\r$ v>ieties are 9 great dem&4 ,to describe adequately _! *>act]i/ics ) relation to light w\ld alone require ! space ( a complete volume1 & ! read] is ref]r$ to ! _m excell5t works on physics 7optics7 :i* are obta9able4 ,?is /one is d\bly refract+1 exhibit+ extremely /rong di*roism1 especially 9 ! blue & ! gre5 v>ieties4 ,x pol>ises light1 & :5 view$ ) ! di*roscope %[s a rem>kable v>iety ( tw9 col\rs4 ,x w be rememb]$ t 9 ,hog>?'s ,rake's ,progress1 ! y\? is too engross$ 9 ! *ang+ wond]s ( a t\rmal9e to notice ! entrance ( ! (fic]s come to arre/ him4 ,,*apt] ,,xv4 ,,v>i\s ,,preci\s ,,/ones--cont9u$4 ,zircon4 ,zircon appe>s to h be5 fir/ discov]$ by ,klapro? 9 #aghi1 9 ! =m ( an e>?1 & six ye>s lat] he f\nd t ! /one hyac9? conta9$ a simil> sub/ance1 bo? hav+ ! =mula1 ,zr,si,o#d1 & bo? hav+ z _! col\r+ ag5t f]ric oxide4 ,!re are sev]al me?ods ( obta9+ ! metallic elem5t1 zirconium2 x is h[ev] ) ! silicate ( zirconium t we h to deal at ! mom5t4 ,?is is call$ zircon1 ,zr,si,o#d1 or hyac9? :5 transp>5t or r$1 b :5 smoke-col\r$1 or col\rless1 x is ! j>goon1 or j>con1 & is f\nd 9 silt & alluvial soils1 lime/one1 gneiss1 & v>i\s =ms ( s*i/1 9 ,india1 ,au/ralia1 ! ,urals1 & c]ta9 p>ts ( ,am]ica4 ,x is (t5 comb9$ ) & f\nd 9 juxtaposition to gold & c]ta9 v>ieties ( preci\s /ones4 ,! l9es ( cleavage are p>allel to ! sides ( ! prism1 & ! cry/als h an adamant9e1 or diamond lu/re1 v>y+ f ! completely opaque to ! transp>5t4 ,9 "s v>ieties ! oxide ( uranium is also pres5t 9 traces4 ,x cry/allises 9 ! #crd 7tetragonal7 sy/em1 ) indi/9ct cleavage4 ,its specific gravity v>ies f #d4gj to #d4hh1 accord+ to ! specim5 & ! locality4 ,?is /one1 l "s ( ! o!rs describ$1 has a v wide range ( col\r1 go+ ?r\gh r$s1 br[ns1 gre5s1 yell[s1 oranges1 :ites1 greys1 blues f light to indigo1 not)/&+ :i* x is some:at difficult to imitate sci5tifically1 ?\gh its composition ( #cc p] c5t4 ( silica ) #fg p] c5t4 ( zirconia 7! oxide ( zirconium71 is practically all x conta9s1 ap>t f ! col\r+ matt]1 su* z ! metallic oxides ( iron1 uranium1 etc4 ,its h>dness is #g-a_/b1 consequ5tly x is unt\*$ by a file1 & s f>1 if "o or p]haps two ( ! ?ree qualities ( col\r1 h>dness1 & specific gravity1 are obta9$ 9 a *emically made zircon1 ! ?ird is want+4 ,"u ! bl[pipe1 zircons are infusible1 b ! col\r$ /ones :5 heat$ /rongly become heavi]1 & z !y are contract+1 _! col\r fades1 sometimes entirely1 :i* *anges are p]man5t1 s t z !y possess ! adamant9e lu/re1 !y are occasionally cut l a diamond1 & us$ z su*1 ?\gh _! defici5cy 9 fire & h>dness1 & _! high specific gravity1 make !m readily di/+ui%able f ! diamond4 ,on exposure to light ! col\r$ zircon becomes m or less decol\r$2 especially is ?is s 9 sunlight1 = :5 ! direct rays ( ! sun fall ^u x1 ! col\rs fade1 & = a mom5t or two occasional phosphoresc5ce foll[s1 z is ! case :5 ! /one is w>m$ or heat$ 9 a d>k room4 ,! /one appe>s to be v susceptible to brilliant light-rays1 & 9 c]ta9 specim5s :i* 7 split = te/+1 "o half ( ea* be+ kept exclud$ f light = purposes ( comp>ison1 x 0 f\nd t sun%9e affect$ !m mo/2 !n brilliant acetyl5e gas1 :i* 0 m effective /ill :5 t9t$ yell[ by be+ pass$ ?r\gh yell[ glass4 ,! electric arc 0 n s effective1 b ! electric light ( ! m]cury-vap\r lamp1 ?\gh caus+ little *ange at ! fir/1 aft] a few h\rs' exposure rapidly blea*$ c]ta9 ( ! col\rs1 :il/ hav+ no effect on o!rs4 ,coal gas ) inc&esc5t fibre mantle 0 slightly effective1 :il/ ! coal-gas1 burn$ direct ?r\gh an ord9>y burn]1 affect$ v few ( ! col\rs1 ev5 aft] tw5ty-f\r h\rs' exposure at a di/ance ( ?ree feet4 ,9 all ^! cases1 ?\gh ! col\rs 7 slightly improv$ by ! /ones be+ kept = a "t 9 ! d>k1 !y fail$ to recov] _! orig9al /r5g?1 %[+ p]man5t loss ( col\r4 ,! ,silicates4 ,! *ief ( ^! are ! g>nets1 cry/allis+ 9 ! cubic sy/em1 & anhydr\s4 ,! g>net is usually 9 ! =m ( a rhombic dodecah$ron1 or z a trisoctah$ron 7call$ also sometimes an icosatetrah$ron71 or a mixture ( ! two1 ?\gh ! /ones appe> 9 o!r cubic =ms4 ,9 h>dness !y v>y f #f-a_/b to #h-a_/b4 ,!y av]age f #dj to ab\t #db p] c5t4 ( silica1 ! o!r +r$i5ts be+ 9 fairly con/ant & def9ite proportions4 ,!y are vitre\s & res9\s 9 _! lu/re & ( great v>iety ( col\r1 *iefly among/ r$s1 purples1 violets1 gre5s1 yell[s & blacks1 accord+ to ! col\r+ matt] pres5t 9 _! mass4 ,!re are _m v>ieties :i* are nam$ 9 accordance ) "o or m ( _! con/itu5ts1 ! be/ kn[n be+3 7,a7 ,! iron-alum9a g>net1 hav+ ! =mula #f;,fe,o1 #c,si,o#b #b;,al#b,o#c1 #c,si,o#b4 ,?is is ! preci\s g>net1 or alm&9e1 sometimes call$ ! ,ori5tal g>net2 ^! /ones are f\nd 9 ,great ,brita91 ,india1 & ,s\? ,am]ica1 & are deep r$ & transp>5t1 ( vitre\s lu/re4 ,!y get up well1 b c]ta9 v>ieties are s subject to defects 9 _! sub/ance1 br\ght ab\t by pressure1 volcanic action1 & o!r causes1 "s ( :i* are n yet kn[n1 t _! quality (t5 becomes mu* depreciat$ 9 consequ5ce4 ,?is inf]ior v>iety ( ! iron-alum9a g>net is call$ ! common g>net1 & has little lu/re1 be+ sometimes opaque4 ,! p]fect qualities1 or alm&9e1 z describ$ above1 are fav\rite /ones ) jewell]s1 :o m\nt great quantities ( !m4 ,! second v>iety is ! 7,b7 lime-iron g>net1 =mula1 #f;,ca,o1#c,si,o#b #b;,fe#b,o#c1c,si,o#b4 ,! *ief ( ?is class is ! melanite1 sometimes dull1 yet (t5 vitre\s2 x is mo/ly f\nd 9 volcanic rocks1 su* z tuff2 ?is v>iety is v popul> ) jewell]s = m\rn+ ornam5ts1 = z x is a beautiful velvet-black 9 col\r & q opaque1 x is pre-em95t = ?is purpose1 be+ consid]ably less brittle ?an jet1 ?\gh heavi]4 ,ano!r v>iety is ! topazolite1 bo? yell[ & gre54 ,! aplome is gre5i%-yell[1 yell[i%-gre51 br[n1 & usually opaque4 ,a fur!r =m ( lime-iron g>net is ! pyr5eite1 fir/ f\nd 9 ! ,pyr5ees ,m\nta9s1 h5ce its "n4 ,! 7,c7 lime-*rome g>nets--#f;,ca,o1#c,si,o#b #b;,cr#b,o#c1 #c,si,o#b--! *ief ( :i* is uw>[ite4 ,?is is ( a magnific5t em]ald gre5 col\r1 transluc5t at edges & ( a vitre\s lu/re4 ,:5 heat$ on ! borax bead x gives an equally beautiful gre51 :i* is1 h[ev]1 r m incl9$ to *rome ?an em]ald4 ,?is is an extremely r>e /one 9 f9e col\r1 ?\gh cl\dy & imp]fect specim5s are (t5 met )1 b seldom are l>ge /ones f\nd )\t flaws & ( ! pure col\r1 :i* rivals t ( ! em]ald 9 beauty4 ,! f\r? v>iety 7,d7 is ! lime-alum9a g>net1 its =mula be+--#f;,ca,o1#c,si,o#b #b;,al#b,o#c1c,si,o#b4 ,l ! o!rs1 x has a numb] ( sub-v>ieties1 ! *ief be+ ! c9namon /one1 :i* is "o ( great beauty & value :5 p]fect4 ,?is /one is almo/ always transp>5t :5 pure1 :i* prop]ty is usually tak5 z "o ( ! te/s ( its value1 = ! slighte/ admixture or pres5ce ( o!r sub/ances cl\d x1 probably to opacity1 9 accordance ) ! quantity ( impurity exi/5t4 ,?is v>iety is compos$ ( ! oxides ( alum9ium & silicon ) lime4 ,9 col\r x ranges f a beautiful yell[i%-orange deep5+ t[>ds ! r$ to a pure & beautiful r$4 ,romanzovite is ano!r beautiful v>iety1 ! col\r ( :i* ranges ?r\gh br[ns to black4 ,ano!r important v>iety is ! succ9ite1 :i* gets up well & is a fav\rite ) jewell]s because ( its beautiful1 amb]-l col\r1 )\t possess+ any ( ! drawbacks ( amb]4 7,e7 ,! magnesia-alum9a g>net--#f,mg,o1#c,si,o#b #b;,al#b,o#c1c,si,o#b--;is some:at r>e1 ! mo/ frequ5tly f\nd be+ ( a /rong crimson col\r & transp>5t4 ,?is v>iety is call$ pyrope1 ! deep] & ri*] t9ts be+ designat$ c>buncle1 f ! ,lat9 c>bunculus1 a little coal1 because :5 ?is beautiful v>iety ( ! noble g>net is held up betwe5 ! eyes & ! sun1 x is no long] a deep1 blood-r$1 b has exactly ! appe>ance ( a small piece ( live or gl[+ coal1 ! sc>let portion ( its col\r-mixture be+ p>ticul>ly evid5t4 ,! anci5t ,greeks call$ x an?rax1 :i* "n is sometimes us$ 9 m$ic9e to-day ) ref]5ce to ! sev]e boil-l inflammation :i*1 f its burn+ & r$ness1 is call$ a c>buncle1 ?\gh x is m usual to apply ! ^w an?rax to ! malignant cattle-disease :i* is occasionally pass$ on to man by means ( wool1 hair1 blood-clots1 etc41 etc41 & almo/ always ends fatally4 ,a great deal ( my/]y & sup]/ition has always exi/$ 9 connexion ) ?is /one--! invisibility ( ! be>] ( ! egg-c>buncle laid by a goldf9*1 = in/ance4 7,f7 ,! manganese-alum9a g>net--#f,mn,o1#c,si,o#b #b;,al#b,o#c1c,si,o#b--;is usually f\nd 9 a cry/all9e or granul> =m1 & mo/ly 9 granite & 9 ! int]/ices ( ! plates1 or lam9ae1 ( rocks call$ s*i/4 ,"o v>iety ( ?is1 :i* is a deep hyac9? 9 col\r1 ?\gh (t5 ( a br[n-t9t$ r$1 is call$ spess>t9e1 or spess>tite1 f ! di/rict 9 :i* x is *iefly f\nd1 ?\gh its di/ribution is a fairly wide "o4 ,! ,lapis-,lazuli4 ,! lapis-lazuli1 sometimes call$ azure /one1 is almo/ always blue1 ?\gh (t5 conta9+ /reaks ( :ite & gold col\r1 ! latt] ( :i* are due to ! pres5ce ( m9ute specks or ve9s ( iron pyrites1 ! =m] & col\rless /reaks be+ due to free lime1 calcite1 & o!r sub/ances :i* h become m or less bl5d$ ) ! blue col\r ( ! /one4 ,x has a vitre\s lu/re1 cry/allises 9 ! #a/1 or cubic sy/em1 & is a complex sub/ance1 v>y+ consid]ably 9 its +r$i5ts 9 accordance ) ! locality 9 :i* x is f\nd1 its matrix1 & ! g5]al geological =mation ( ! surr\nd+ sub/ances1 :i* may1 by ! p5etration ( moi/ure1 be br\ght to be> ^u ! /one1 ?us influ5c+ to a great ext5t its *emical composition4 ,s t we f9d ! /one compos$ ( ab\t a qu>t] ( its sub/ance ( alum9a1 or oxide ( alum9ium1 silica to ! ext5t ( almo/ half1 ! rema9d] be+ lime1 soda1 sulphur1 & occasionally traces ( copp] & iron4 ,x is mo/ly f\nd 9 granite & c]ta9 cry/all9e lime/one rocks1 9 fairly l>ge masses4 ,x is ( great antiquity1 figur+ ext5sively 9 anci5t ,egyptian hi/ory1 bo? 9 its =m z a /one & gr\nd up into a pigm5t = ! decoration ( sacr$ & royal vessels & appo9tm5ts4 ,:5 s gr\nd1 x =ms ! /able & magnific5t col\r1 g5u9e ultram>9e1 :i* is ! f9e/ & pure/ blue on ! arti/'s palette1 b ow+ to its extremely high price its use is n 9 v great dem&1 especially z _m excell5t *emical sub/itutes ( equal p]man5ce are obta9able at little co/4 ,! ,turquoise4 ,! turquoise is a pseudomorph 7see ,*apt] ,,iv41 ,cleavage47 ,9 col\r x is blue or gre5i%-blue1 sometimes opaque1 v>y+ betwe5 t & feeble transluc5cy1 ?\gh x %\ld be said t 9 all =ms1 ev5 ^? consid]$ opaque1 a ?9 cutt+ ( ! /one appe>s almo/ transp>5t1 s t ! usual class+ ( x among ! opaque /ones mu/ be done ) ?is res]vation4 ,9 composition x conta9s ab\t #bj p] c5t4 ( wat]1 ab\t a ?ird ( its sub/ance be+ phosphoric acid1 or phosphorus-p5toxide2 sometimes ne>ly half ( x is alum9a1 ) small quantities ( iron 9 ! =m ( v>i\sly col\r$ oxides1 ) oxide ( manganese4 ,! great proportion ( wat]1 :i* x seems to take up dur+ =mation1 is mo/ly obta9$ 9 ! cavities ( wea!r$ & moi/ure-decompos+ rocks4 ,its av]age =mula may be said to be ,al#b,o#c,p#b,o#e #e;,h#b,o1 & sometimes ,al#b,o#c ,fe,o,p#b,o#e #e;,h#b,o4 ,x mu/ !re=e foll[ t :5 ! /one is heat$1 ?is wat] w sep>ate & be giv5 (f 9 /eam1 :i* is f\nd to be ! case4 ,! wat] comes (f rapidly1 ! col\r ( ! /one alt]+ mean:ile f its blue or blue-gre5 to br[n4 ,if ! heat is cont9u$ suffici5tly long1 ?is br[n w deep5 to black1 :ile ! flame is turn$ gre54 ,?is is "o ( ! te/s = turquoise1 b z ! /one is de/roy$ 9 ! process1 ! exp]im5t %\ld be made on a spl9t] f x4 ,?is /one is ( v anci5t orig91 & _m old turquoise deposits1 n[ empty1 h be5 discov]$ 9 v>i\s places4 ,hi/ory records a magnific5t turquoise be+ (f]$ 9 ,russia = ab\t ,l#hjj a few c5turies ago1 :i* is a v high price = ^! comp>atively common /ones4 ,ow+ to ! pres5ce ( phosphorus 9 bones1 x is n uncommon to f9d1 9 c]ta9 caves :i* h be5 ! resort ( wild animals1 or into :i* animals h fall51 t bones 9 "t become subject$ to ! ooz+ & moi/ure ( _! surr\nd+s2 alum9a1 z well z ! oxides ( copp]1 manganese & iron1 are (t5 wa%$ across & ov] ^! bones ly+ on ! cave floor1 s t 9 "t1 ?is silt acts on ! sub/ance ( ! bones1 =m+ a v>iety ( turquoise ( exactly ! same composition z t j describ$1 & ( ! same col\r4 ,s t ar\nd ! bones !re ev5tually appe>s a beautiful turquoise cas+2 ! bone c5tre is also col\r$ l its cas+1 ?\gh n entirely los+ its bony *>act]i/ics1 s t x really =ms a k9d ( ossifi$ turquoise1 surr\nd$ by real turquoise1 & ?is is call$ ! bone turquoise or odontolite4 ,,index ,adamant9e lu/re1 #bh glimm]+1 #bi gl9t+1 or gli/5+1 #bi lu/reless1 #bi %9+1 #bi spl5d5t1 #bi ,agate1 #aa ,alm&9e1 #aja ,ame?y/1 #aa ori5tal1 #he sapphire1 #he ,amorph\s /ones & _! *>act]i/ics1 #bc ,analysis1 #e ,aplome1 #aja ,a/]s1 or a/]iat$ /ones1 #hb1 #hg-ia ,azure-/one1 #ajc ,b]yl1 #aj1 #id col\rs (1 9 di*roscope1 #cd ,b]yllium1 #aj ,bezils1 #ff ,black /ones1 li/ (1 #gi ,blue sapphire1 composition ( !1 #aj /ones1 li/ (1 #gg ,bone-turquoise1 #ajf ,break1 z oppos$ to cleavage1 #ai ,brilliant-cut /ones1 #ff ,br[n /ones1 li/ (1 #gf ,build+ up ( cry/als1 #ac ,burnt1 or p9k$ topaz1 #ib ,cabo*on-cut /ones1 #fd 7! d\ble71 #fe 7! holl[71 #fe ,c>bonate s]ies1 #aa ,c>buncle1 #ajb1 #ajc ,cat ( ,egypt1 #hi ,cat's eye /ones1 #hb1 #hg-ia li/ ( 7see ,*atoyant ,/ones71 #gh ,ceylonese cat's eye 7see ,cat's eye7 ,*ange ( col\r 7n to be confus$ ) ,play ( col\r & ,opalesc5ce1 :i* see2 see also ,fire71 #cf ,*>act]i/ics ( preci\s /ones1 #a1 #c ,*atoyant /ones1 li/ (1 #gh ,*emical illu/ration ( =mation ( preci\s /ones1 #h ,*loride ( palladium 9 di*roscope1 #cd ,*rysob]yl1 #hh ,*rysolite1 #aa ord9>y1 or noble1 #he ori5tal1 #he ,c9namon /one1 #ajb ,claims ( preci\s /ones1 #d ,cleavage affect+ te/s1 #dc & cleavage z oppos$ to break1 #ai1 #bb ,col\r1 #bf1 #bh1 #cj1 #cb ,col\rless /ones1 li/ (1 #ge ,col\rs & *>act]i/ics ( ! v>i\s opals1 #ce1 #cf ( preci\s /ones1 li/ (1 #ge-gi ,common g>net1 #aja opal1 #ce ,composite cry/als1 #ac ,composition ( pa/e1 or /rass1 = imitation /ones1 #ga ,composition ( preci\s /ones1 #g ,conv]t$ /ones1 #gb ,corundum1 #hb ,cr[n portion ( /ones1 #fe1 #ff ,cry/all9e /ructure1 physical prop]ties1 ( #ac ,cry/allography1 #ad ,cry/als1 axes ( symmetry1 #ae gr\ps (1 #ae1 #af planes ( symmetry1 #ae sy/ems (1 #af 7#a7 ,cubic--isometric1 monometric1 regul>1 #af 7#b7 ,hexagonal--rhomboh$ral1 #af 7#c7 ,tetragonal--quadratic1 squ>e prismatic1 dimetric1 pyramidal1 #af 7#d7 ,rhombic--or?orhombic1 prismatic1 trimetric1 #af 7#e7 ,monocl9ic--cl9orhombic1 monosymmetric1 oblique1 #af1 #ag 7#f7 ,tricl9ic--anor?ic1 asymmetric1 #af1 #ag treatm5t (1 #ad ,culasse portion ( /ones1 #ff ,cull9an diamond 7see also ,/>s ( ,africa71 #bb1 #fd1 #fh1 #hj ,cutt+ ( preci\s /ones1 #c1 #d1 #fb ,cymophane1 #ij ,def9ition ( a preci\s /one1 #a ,diamond1 *>act]i/ics ( !1 #hj composition ( !1 #aj 7sapphire71 #hf unique1 #aj 7zircon71 #ii ,diaphaneity1 #bf1 #bh ,diaphan\s /ones1 #bh ,di*roscope1 #cc h[ to make a1 #cc h[ to use a1 #cd ,dimorphism 9 preci\s /ones1 #be ,d\ble cabo*on-cut /ones1 #fe refraction 7see ,refraction7 ,d\blets1 #gb ,electric & magnetic influ5ces1 #eg exp]im5ts ) preci\s /ones & pi?ball & electroscope1 #eg exp]im5ts ) t\rmal9e1 #eh1 #ei ,em]ald1 #aj1 #aa1 #ie1 #if ori5tal1 #he ,en cabo*on-cut /ones1 #fd ,exp]im5ts to %[ electric pol>ity1 #eh1 #ei ,facets 9 /ones1 description ( !1 #fg1 #fh ,fem99e /ones1 #he ,fire 9 /ones 7see also ,*ange ( ,col\r1 ,opalesc5ce1 & ,play ( ,col\r71 #cf1 #cg ,fire opal1 #ce ,flame-col\r$ /ones1 li/ (1 #gf ,flaws1 #fc ,=mation ( preci\s /ones1 #e1 #h *emical illu/ration (1 #h1 #i ,g>net1 #aa1 #ajj ,g>nets 7,a7 iron-alum9a 7call$ also alm&9e & preci\s or ori5tal g>net71 #aja sub-v>iety1 common g>net1 #aja 7,b7 lime-iron1 #aja sub-v>iety aplome1 #aja melanite1 #aja pyr5eite1 #aja topazolite1 #aja 7,c7 lime-*rome1 #aja1 #ajb sub-v>iety uw>[ite1 #aja1 #ajb 7,d7 lime-alum9a1 #ajb sub-v>iety c9namon /one1 #ajb romanzovite1 #ajb succ9ite1 #ajb 7,e7 magnesia-alum9a1 #ajb1 #ajc sub-v>iety c>buncle1 or an?rax1 #ajb1 #ajc noble1 #ajc pyrope1 #ajb 7,f7 manganese-alum9a1 #ajc sub-v>iety spess>t9e1 or spess>tite1 #ajc ,girdle portion ( a /one1 #ff ,glimm]+1 9 lu/re1 def9ition (1 #bi ,gl9t+1 or gli/5+ 9 lu/re1 def9ition (1 #bi ,g\tte de suif-cut /ones1 #fe ,great ,mogul diamond1 #fd ,gre5 /ones1 li/ (1 #gh ,gr\ps ( cry/als 7see ,cry/als7 ,h>dness1 physical prop]ties (1 #ci table (1 #ci1 #dj1 #da ,heat indexes1 #ed physical prop]ties (1 #eb ,holl[-cabo*on1 #fe ,hyac9?1 ord9>y 7a =m ( zircon71 #he1 #ih ori5tal1 #he ,hyalite 7opal71 #ce ,hydrophane 7opal71 #ce ,imitations & te/s ( preci\s /ones1 #gj ,indigo sapphires1 #hf ,ink sapphires1 #he ,iridesc5ce1 & cause (1 #cg1 #ch ,iron-alum9a g>nets1 #aja ,jac9?1 ori5tal1 #he ,j>con1 or j>goon1 #ih ,koh-i-nur1 #fd ,lapis-lazuli1 #ajc ,light1 physical prop]ties (1 #bf ,lime-alum9a g>nets1 #ajb c9namon /one1 #ajb romanzovite1 #ajb succ9ite1 #ajb ,lime-*rome g>nets1 #aja1 #ajb uw>[ite1 #aja1 #ajb ,lime-iron g>nets1 #aja aplome1 #aja pyr5eite1 #aja topazolite1 #aja ,li/ ( /ones accord+ to col\r1 #ge-gi h>dness1 #ci-da specific gravity1 #dh-ej ,lu/re1 #bf1 #bh ,lu/reless1 def9ition (1 #bi ,lynx-eye /ones1 #hg ,magnesia-alum9a g>nets1 #ajb1 #ajc c>buncle1 or an?rax1 #ajb noble1 #ajc pyrope1 #ajb ,magnetic & electric influ5ces1 #eg-fa ,mala*ite1 #aa ,manganese-alum9a g>nets1 #ajc spess>t9e1 or spess>tite1 #ajc ,mascul9e /ones1 #he ,melanite1 #aja ,m5ilite 7opal71 #cf ,metallic-lu/re /ones1 #bh1 #bi ,mohs's table ( h>dness1 #ci-da ,noble g>net1 #ajc or preci\s opal1 #ce ,non-diaphan\s /ones1 #bh ,odontolite1 #ajf ,oliv9e corundum 7see ,*rysolite71 #he ,opal1 #aa v>ieties (1 #ce1 #cf ,opalesc5ce 7n to be confus$ ) ,*ange ( ,col\r & ,play ( ,col\r1 :i* see2 see also ,fire71 #cf1 #cg ,ori5tal ame?y/1 #he cat's eye 7see ,cat's eye7 em]ald1 #he g>net1 #aja topaz1 #he ,orig9 ( preci\s /ones1 #g ,pa/e1 or /rass1 = imitation /ones1 composition (1 #ga ,pavilion portion ( cut /ones1 #ff ,pe>ly-lu/re /ones1 #bh1 #bi ,p]idot 7see ,noble ,*rysolite71 #he ,p9k-col\r$ /ones1 li/ ( 7see also ,r$71 #gg ,p9k$ topaz1 #ib ,phosphoresc5ce1 #bf1 #cj ,physical prop]ties3-- ,a4--,cry/all9e /ructure1 #ac ,b4--,cleavage1 #ai ,c4--,light1 #bf ,d4--,col\r1 #cb ,e4--,h>dness1 #ci ,f4--,specific gravity1 #de ,g4--,heat1 #eb ,h4--,magnetic & electric influ5ces1 #eg ,play ( col\r 7n to be confus$ ) ,*ange ( ,col\r & ,opalesc5ce1 :i* see2 see also ,fire71 #cf1 #cg ,pleo*roism1 #cc ,pol>isation1 electric1 #eh1 #ei ( light1 #bf1 #bg ,pol>iscope1 #bg1 #bh ,poli%+ preci\s /ones1 #c1 #d ,polymorphism 9 preci\s /ones1 #be ,preci\s1 or noble opal1 #ce ,pseudomorphism 9 preci\s /ones1 #bc1 #bd ,pyr5eite1 #aja ,pyro-electricity1 developm5t & behavi\r (1 #eh-fj ,pyrope1 #ajb ,qualities ( preci\s /ones1 #a1 #c ,r$ & rose-col\r$ /ones1 li/ ( 7see also ,p9k71 #gf1 #gg ,reflection ( light1 #bf1 #bh ,refraction ( heat1 #eb-ee light1 #bf1 #bg ,reproduction ( cry/all9e =m1 #bj1 #ba ,res9\s lu/re /ones1 #bh1 #bi ,rock-cry/al1 #aa ,romanzovite1 #ajb ,rose-col\r$ /ones 7see ,r$1 above71 #gf1 #gg ,rose1 or rosette-cut /ones1 #fe ,ro?s*ild's te/+ solution1 #gc ,ruby1 *>act]i/ics (1 #hc composition (1 #aj ,sapphire1 ame?y/1 #he & its v>ieties1 #hd1 #he cle>$1 #hf diamonds1 #hg indigo1 #hf ink1 #he ! blue1 composition (1 #aj1 #he wat]1 #hf ,semi-diaphan\s /ones1 #bh ,%9+1 9 lu/re1 def9ition (1 #bi ,silica gr\p1 composition ( !1 #aa ,silicates1 #ajj ,silky-lu/re /ones1 #bh1 #bi ,s+le-refraction 7see ,refraction7 ,s\? ,african diamond 7see ,cull9an ,diamond7 ,specific gravity1 #de ,spl5d5t1 9 lu/re1 def9ition (1 #bi ,splitt+ ( ! ,cull9an diamond1 #bb ,/>-portion ( /ones1 #fe ,/>s ( ,africa 7see also ,cull9an ,diamond71 #bb1 #fd1 #fh ,/>t+ or splitt+ ( /ones on cleavage planes1 #bc ,/ep-cut /ones1 #ff ,/ones arrang$ accord+ to col\r1 #ge-gi h>dness1 #ci-da specific gravity1 #dh-ej ,/rass = imitation /ones1 composition (1 #ga ,sub-metallic 9 lu/re1 def9ition (1 #bi ,sub-transluc5t /ones1 #bh ,sub-transp>5t /ones1 #bh ,succ9ite1 #ajb ,syn!sis1 #e ,sy/ems ( cry/als 7see ,cry/als7 ,table-cut /ones1 #fe ,tall[ drops1 #fe ,tee? ( /one1 #fe ,te/+ by cry/all9e /ructure1 #ag h>dness1 #dj1 #dc ) ne$les1 #da gems by di*roscope1 #cc1 #cd solution 7,ro?s*ild's71 #gc ,te/s ( preci\s /ones 7g5]al71 #gj ,topaz1 #aa1 #ia col\rs (1 9 di*roscope1 #cd ori5tal1 #he ,topazolite1 #aja ,t\rmal9e1 #if1 #ig electric exp]im5ts )1 #eh1 #ei ,transluc5t /ones1 #bh ,transmission ( heat1 #eb-ef light1 #bf ,transp>5t /ones1 #bh ,trap-cut /ones1 #ff ,tri-morphism 9 preci\s /ones1 #be ,triplets1 #gb ,turquoise1 #ajd 7bone71 #ajf composition ( !1 #aa odontolite1 #ajf ,uw>[ite1 #aja1 #ajb ,violet /ones1 li/ (1 #gh ,vitre\s-lu/re /ones1 #bh1 #bi ,wat]-sapphires1 #hf ,:ite 7pa/e7 /ones1 #ga /ones1 li/ (1 #ge ,yell[ /ones1 li/ (1 #gf topaz1 #ib ,zircon1 #aj1 #ih diamonds1 #ii ,zirconium1 #aj ,,london3 ,,pr9t$ ,,by ,,william ,,cl[es ,,& ,,sons1 ,,limit$1 ,,great ,,w9dmill ,,/reet1 ,w41 ,,& ,,duke ,,/reet1 ,,/am=d ,,/reet1 ,s4 ,e4