146 
EAR 1 HS. SILICEOUS. 42. Gemma. 
double refiailioa : is infufible by the blowpipe : fpecifi*! 
gravity from 3,658. to 3,761. contains alumina 71,5. fili*-* 
18,0. lime 6,0. oxydeefiron 1,5. Klaproth. 
Cbrysolithus Hardifil, pellucid, lightifli, of a green colour which va- 
nillies in a (Iroiig heat, fafible by the blowpipe ao^ 
fparkling when melted, of a conchoidal texture. 
Borax lapidofus. Syst. nat. xii. 3. p, 94. «. 2. b. 
Gemma pellucidiflinia, WalLfiji. l. p. 243. ». 6. 
Chrylolithus. Baum, miner, i, p. 254. 
Chryfolite. Kirwan, l.p. 262. ^homjin ckem. 3. ^.391. 
Chryfolith. Scbmeijfer miner. \ . p. jz 
hound in Brajil, Ceylon, Siberia, ‘T ravfyl<vania, and Bohemia, 
angular fragments, grain.s, and cryllallixed : colour ycllo"'' 
ifh-green mixed with brown, or verging to olive-greef " 
furface of a fine fplintery or Laly appearance, butfuch of th* 
cryftals as have not been injured by friftioir have theb 
broadeft fides longitudinally llriate ; but where the furfac® 
has not fuffered by attrition, it has a confiderable luftf*' 
the regular lhape of its cryftaU is a 6-fided flattened priii*’' 
terminated in 6-fided pyramids, and differs from rock cryll*' 
in having the pyramids more obtufe : fpecific gravity fro**' 
3,265. to 3,450. contains magnefia 41,5. filiea 38,5, oX)'^^ 
of iron 1 9,0. Klaproth. 
Smaragdus. Hard, pellucid, lightifli, grafs-green, when heated 
120 of Wedge wood becomes blue, but recovers 
green colour when cold, melting before the blowpip®’ 
of a conchoidal texture. 
Borax lapidofus. Sy/1. nat. xii. 3./. 95. «. 2. d. 
Gemma pellucidiflima. WaU.Jyft, 1. p. 241. n. 5. 
Emerald. Kir^wan \,p, 247. Thomfon chem. 3.^- 556. 
Emerald. Schmeijfer mineral, \. p.h~j. 
Found in the mountains of Egtpt and Ethiopia, in Peru, 
and the confines of Perfia: colour from the perfett to i" 
pale grafs green : cryftals hexagonal prifms, cither perfeiff 
truncate on the angles and edges, terminating in truncate 
pyramids’: texture foliated : frafture conchoidal ; becoW^* 
eleflric by friflion but not by heat ; caufes a double refi'**'' 
tion ; melts into an opake coloured mafs at 150° of Wedg®' 
wood; fpecific gravity from 2,650, to 2,775. contains fih^ 
64,60. alumina 14,00. glucina 13,00. oxyde of chromi*'"' 
3,50. lime 2,56. moillurc or other volatile ingredient 
K auquelin, 
Soranui, Hard, pellucid, fomewhat ponderous, foliated, of 
hyacinth colour which is permanent in a moder^'^ 
heat, eafily melting in a Itroiig heat into an 
fpumid mafs. 
