f3o 



EARTHS- ARGILLACEOUS^ 38. Mica. 



Found in Bohemia near Bel/u, SeiJfchiZy Laun^ and Lohofan, \ti 

 Wejfo'vzu near Dai'tveilerf in Hungary on monm Schaterf po- 

 rous orcompa<fb, more or lels ponderous, of a reddifh, cine- 

 reous, bkck, blue, iron. Heel or iridefcent colour. 



38, MICA. Confiding of fuica and alumina, with 

 a fmaJI proportion of oxyde of iron, and gene- 

 rally a little mao;nefia and lime : r^iabrous, mea- 

 grey fliining, fpontaneoiifly falling into granular 

 fragments, eafily breaking into difcoid fragments, 

 iightiili, parafitical: fufible before the blow-pipe 

 into a white or coloured enamel. 



membraua" Tranfparent, with large parallel elaftic eafily feparable 



cea. 



lami 



nosa* 



sjpiomosa. 



plates. 



Mica membranacca, Syfi. nat. xii. 3. /. 58, w. i. 



Mica membranacea. WalL/yst. min, i, p. 369, «. i. 



Mica, Mufcovy talc. Kirnjoan mineral. 1,/. 210. 



Mica, Glill. Scbmei/ser mintr. i, p. 176. 



Mica. Thomfon chem. 3. /■ 539. 



Found in Malabar^ Siberia, RuJJia, Finland^ France, and near 

 Geneva, in large plates which are often fublHtured for glafs, 

 and confifts of a great number of thin tranfparent laminae ad- 

 , hering together: thefe are readily difl:ingui(hed from the 

 layers of Gypfum fpcculare and glaciale, from their great 

 degree of flexibility: texture foliated : fragments flat: luftrc 

 metallic I very tough: often abforbs water : feels fmooth, 

 but not greafy : fpecific gravity from 2,6546. to 2,9342. 

 contains filica 50,00. alumina 35,00. oxyde of iron 7,00, 

 magnefia 1,35. lime 1,33. l^'auquelin, 



Tranfparent, coloured, with large parallel eafily fepara^ 

 ble plates. 



Mica membr. fiffilis. Svst. nat. xii. 3./. 58. n. 2. 



Mica membran. femipelluc. Wall. f^H. i,p.^6g^fi. 2. 



Found principally in the granites of primeval mountains, ge- 

 nerally fmoke-colour or black, {"ometimes brown, gold, red, 

 or white, and very rarely concreted in mafles rcfembUng 

 pieces of Shale, 



Somewhat opake, with leffer fcattered incurved foliations, 



1. Of a filvery colour. 



Mica fquamofa argemea, Sj>it. nat, xii. 3. />. 58 «. 3. 



2. Of a gold colour. 



Mica r^uamofa aurata. Sfst^ nat, xii, 3. p. 58, «. 4. 



