Ei^RTHS. SILICEOUS. 43. Ollvinus, 



149 



IVerneri, 



«vitreus» 



^patosus^ 



J^brosust 



43. OLIVINUS. Confiding of the greater part 

 fiiica, and a imalier proportion of aluirina and 

 oxyde of iron: found in bafaltes, fhining inter- 

 nally, generally of a common form, hard, 

 mouldering in the air: melting wich difficulty. 



Tinged, diaphanous, of a conchaceoiis texture, breaking 

 into indeterminate fragments. 

 O ivin. Werner Bergm.Journ. 1790. 7. ^. 5^» 

 Olivin. Kir-wanmin. i.p. 26^. Schinei//er i.p. 73, 

 Olive ChryfoUte, Olivine. Thomjon cheyn. S./". 592. 

 Found in Arthur's feat near Edinburgh in France^ Germany^ and 

 moft parts of Europe^ imbedded in Bafalts, fomeiimes in the 

 form of grain?, fomctimes in large pieces: colour olive or 

 ycllowifh-green, and when withered brownifh or ochre- 

 yellow ; is attacked by digeflion in nitric acid, and its ferru- 

 ginous parts taken up: fpecific gravity from 2,960. to 3,225. 



Pellucid, pure white, of a glally texture; breaking into 

 indeterminate fragments, with the furfaces fpheri- 

 cally convex. 



Hyalite, Mullers glafs. Kirivan minerah l,p. 296. 



Hyalite. Ihomfon chem^ 3, p. 563. 



Found in Germany^ Hannonjer. and francfort^ in rocks of trap 

 or ferpentine, and occurs in the form of grains, hlamcnts or 

 rhomboidai mafles : texture foliated: fradure inclining to 

 rhomboidal : is generally tranfparent, fometimes, though 

 feldom, opake : is infufible at 150° of Wedge.vood, tut 

 yields to Soda: fpecific gravity 2,1 10. contains fiiica 57. 

 alumina i8: lime 15 ; and a very little iron. Link. 



Diaphanous, white, of a foliated texture, breaking inta 



rhomboidal fragments. 



Feldfpat. 'Nofe Orogr, Brief, i. p. 224. 



Found in Gotttingen in Safalt, and on mount Mendenhurg on 



the^^/«f; relembles F^ldfpar, but is haraer, and much 



more difficult of fufion. 

 t 



Diaphanous, white, fibrous, hard, fhining. 

 V, H, Miner, Beob. Bafak.. a, Rhcin, p, 1 1 1 , 

 Found on the banks of the Rhiney n.ar Unkalj imbed>,Icd i;^ 

 bafalt, and is very brittle, 



