EARTHS. SILICEOUS. 42. Gemma. 147 



Hyacinthus Gemma. Cronst. miner. 69. A. 2. o. 



Gemma Granite?. Wall. fyji. min. I. p. 253. », 4. a. b. 



Found in S-cvitzerlafid^ Nurnjuayj Greenland, and the mountains 

 of Siheria, in Braf'il and Ceylon, fomttimes in the form of 

 rounded grnns mixed with fand or earth, fometimes imbed- 

 ded in other ftcnes, in 6-fidcd clyllals terminated each fide 

 bv a 3-rided pyramid : is twice as hard as fpar, and lofes its 

 colour when fprinkled with the flronger mineral acids, 



Gramtus, Hard^ ponderoiu, red^ of unequal texture, preferving its 

 coiour in a low heat, melting in a (Ironger heat into a 

 brown opake fpumid mafs. 



Borax teilcllatus. 6y/L nat, xil. 3./ 72. «. 5. 



Gemma plus minus pellucida. fFal/. min, 117. 



,Gr- met. Carbuncle. Kirivan mineral. i./», 258. 



G rnit, Sckmejfer minerah i. /• 69. 



^Garnet. "Thomjot chem. Z* P- S7^' 



Silex Granatus, Soberly Brit, min, ^.43, 44. 



1. Pellucid. 



Gra.nat. cry llal. pellucid. Walhfyji% l* p. 2^7. n^^. 



2. Opake. 



Granat. cryftal. opac. JVall./yst. i, p. 253. n. 3. 

 Bor..x margodes. 6)//. nat* xii. 3. ^. 73. »• 6, 



3. Breaking into granular fragments. 



Gra. at. fig. indeterm. Wall.fyji. i. p. z^O. n. J. 

 Granat. partic. granulat. Cronst, miner, 69. A, i. 



^4. Breaking into cruftofe fragments. 



Granat, fig. indeterm. Wall, fyji, I,/. 251. n, 2. 



5._ Of a common form. 



6. In the form of loofe rounded grains with the angles worn off, 



and found in rivers, the common foil, ar.d among fand. 



7. In the form of cfyftals, and generally imbedded in a matrix, 



light. 



a. In double ^-fided pyramid?, 

 With the tips truncate, 

 Gmei.fyst. nat. 3. p, 447. t, I, f, 36, 



b. In double 8-fided pyramids. 



Each fide augmented by another 4-fided deprelTed pyramid, 

 Amcen acad. \, />. 482. 



c. In 3fided pyramids, with the margins of the fides and bafe 



truncate. 

 Gmel, fyst. nai. 3. p, 447, /. 1./. 37. 



d. In 6-fided pyramids, with tiie margins of the bafe truncate. 

 Gmel, fyst ^ nat, 3, p, 445, t. \, f, 2. 



T 2 



