386 DR T, THOMSON on Asbestus, Chlorite, and Talc. 



and alumina, with a certain quantity of water. We may state 

 the constituents as follows : 





 12 atoms sesquisilicate of magnesia, 



'5 atoms sesquisilicate of alumina, 

 21 2 atoms water. 



Soapstone thus constitutes a peculiar species. It resembles 

 mica, in being a compound of sesquisilicates. But the number 

 of salts combined in it is much fewer, and mica {at least rhom- 

 boidal mica) contains no magnesia, which constitutes so conspi- 

 cuous an ingredient in soapstone. 



~2. Agalrhatolite. 



r\J . ' 



This mineral, which comes from China, usually cut into va- 

 rious figures, and on that, account . called figurestone, bildstein, 

 has been classed along with soapstone, though the resemblance 

 which it bears to the characters of that mineral is not very close. 



Its colour varies considerably ; but that of the specimen 

 which I subjected to analysis was white, with a shade of bluish- 

 green. 



Lustre waxy and nearly dull. It acquires some lustre in the 

 streak. 



Fracture splintery ; rather sectile. 



Translucent; tough; feel soft. ,, 



Not scratched by calcareous spar ; but readily by fluor-spar. 

 It seems to have nearly the hardness of calcareous spar. 



Specific gravity 2.895. 



