MODE IV. STEATITE. 



of Corsica, crystallised in hexagonal plates, 

 placed horizontally; and which are only, he 

 says, distinguishable from mica as they are 

 duller, and are oily and unctuous. 



" I have similar crystals, which are found in- 

 laid in topazes and emeralds of Siberia; and as 

 I perceive the insensible transitions from pure 

 mica to this unctuous mica, I look upon this 

 last as a simple modification, or perhaps the 

 commencement of the decomposition of the real 

 mica. 



" Saussure has observed on Mount Cervin, 

 near Mount Rosa, a steatite which he has called 

 specular. It terminates the last rock before the 

 snow. He has given it that name because its 

 surface is as smooth as a mirror, and as polished 

 as this species of rock admits. Its colour is a 

 very dark bottle-green; its fracture irregularly 

 schistose ; it is soft, and is easily scratched with 

 grey streak*. 



" Saussure has elsewhere seen, and particu- 

 arly near the convent of Mount St. Bernard, a 

 arge rock of a quartzy nature, whose entire 

 urface is polished so as one may see one's self 

 n it, as in a looking-glass. He justly regards 

 this phenomenon as an effect of crystallisation. 



* See Sams. 2258. 

 VOL. I. Y 



