GEMS. 
cm0, ‘to whic 
e th 
e fine 
reen- 
cre- 
purpofes 
 Chryfopras.—This femi-tranfparent ftone, of a — ully 
apple- jae pafling into grafs-green, deferves: to 
with the gems or precious ones, as well on a ocean ws its* 
hardael, w which. far exceeds that of an its fpecific gr avity, 
value as an articl 
expofed to moifture aa to heat. tad aries even Berea 
that great care fhould be aces in polifhing it; for . for 
want ient moifture, or too rapid motion 
co) t 
‘of the wheel, it be Or agenda in a a&t of polithing it, it 
_Brackmann pee 
ut the 
the gems. fine 
have been’ frequently hie at the price of one . he 1e 
ae partia 
eae te 
Mar oe But it is very ‘probable that a of 
the ftones deferibed we ancient ee Sie weitere ee 
ie In 
tiful o 
ee: Verner. 
$ oF ad eS, 
cularly am or pve: ie rs, sae ring fometint mes in ue 
eae of burni ning ee) extinguifhed charcoal; the qwine- 
opal, which, when etween the eye and the light, 
ae “yellowired proton eos appear quite 
n viewed in pion, it is called g which name 
ftar 
is alfo given to ie co 
white, fometimes ne imperfe@tly tranfparent, appearing 
blueifh and reddith blue when held againk the lig!t, and offer-- 
ing here and there {mall fpecks of green and pur ple. neg 
"the a al, a dark seh one ated por 
1e 
by a skig the 
the 
in wa 
ee bee opacity 2 as ree as aad 
porated), is fometimes fet in rings au jour, 
which even the enallets os thefe flones were formerly folds ‘Is 
ana i chy te olivine, a by: Hai under the 
e of Phe 
efuviany: ( idocréfe of Hatiy,) known alfo by the name 
. he eusiae ney OF oe volcanic hyacinth, is aera hard 
o fer quartz 3 its cae Ee, is 
feafibly “double-reftaétin ng 3 colou 
the pri imitive fom 
cryftals, which have a polifhed fhining furface, is a very 
fhort prifm with {quare bafe ; Conte ry cry als are © 
formed truncation of all Aa ESU-~ 
