144 
EARTHS. SILICEOUS. 42. Gemma. 
foliated texture : they are imitated by heating rock cryftal* 
and putting them into a folution of dragon’s-blood : con- 
tain.' alumina 40. carbonate of lime 20. oxyde of iron 1 3* 
Bergman. 
alahaiidica. Hard^ pellucid, of a red colour, not fufible but lofing its 
colour in a Itroiig heat. 
Ferher n. Beysr. mineral. I.^. 585, 
hovind in the river Gaetch near Lengefeld, in the form of rounded 
granulations, from the fize ol a pea to that of a bean ; when 
expofed in a llrong heat ferrounded with wood-alhes, lofe® 
all its colour, and is often fold for the Diamond. 
Rubkellui. Hard, of a reddilli colour verging to pale yellow, not fufi- 
blc but lofing its colour in a Itrong heat. 
Rubinus col. rubeo fubflavo. bVatl. jyst. 1. p. 236. n. z. d. 
Occidental or Brafilian Ruby. Kirnvan min. j. p. 254. 
Found in the Eati Indies : is fofter than the Topaz, and of * 
•much inferior colour: fraflure foliated. 
Spinellus, Hard, of a pale red colour inclining to orange, not fufibR 
but lofing its colour in a llrong heat. 
Rubin, col. rubeo fubalho. IFall. Jyfl. 1 . p. 236. ». 2. c. 
Spinell and BiUfs Ruby. Kir-wan miner. \ .p. 253. 
SpinclI. SchmeiJJer miner. 1. 61. 
Spinell. Fhomfonchem. 3. p. 514. 
Found in Ceyhn, in S-fided cryllah, conlifting of 2 pyramids* 
each of 4 planes, and joined bale to bafe; or triangular, or 
trapezoidal plitc< bcvilled on the edges : texture foliated 1 
fraaure conchoidal : fpecific gravity frem 3,570. to 3,625. 
contains alumina 76. filica 16. inagnefia 8. oxyde of iron 
1,5. Klaproth t 
Jqua mari. Hard, pellucid, lamellar, pale fea-green, not fiifiblc 
na. per fe, breaking into trapezoidal fragments. 
Borax lapidofus. S-yst. nat.xn. 3. p. 95. ». z. c. 
.Srnaragdus. Wall.jiJi. min, i. p. 242. n, 5, c. 
Bervll. Kirwan miner. 1. p. 248. 
Aquamarine, Beryl. Schmeiffer miner, i. p. 66. 
Beryl, or .'fqua Marina. Thomfou chem. 3. p. 557. 
Found in Brajtl, India, Siberia, Saxony, and Bohemia, fome- 
times amorphous, fometimes cryllallized in equiangular 6- 
fided prifms longitudinally llriatcd : its longitudinal frafture 
rather conchoidal, its traniVerfc fraflure foliated i colour 
rarely a biuifli-grecn : it decrepitates when heated, and i< 
generally a little difcolourcd, but does not melt : become* 
elctlric by fricUon, when one of its ends is attraftive, the 
other repulfive: fpecific gravity from 3,521. to 3 , 54 ^' 
contains filica 69. alumina 13. glucina ib. oxyde of iros 
I. lime 0,5. Vauiuelin. 
