262 



A more compact variety of the white mineral aiforded : — 



0.08 



99.83 

 The analysis of an average specimen, which exhibited the 

 greenish-black, light green, and white colors intermixed, gave as 

 its component parts : — 



Moisture 0.40 



Carbonate of Magnesia .... 38.00 

 Talc and Serpentine 61.60 



61.37 



The basis rock is therefore an indefinite mixture of serpen- 

 tine and greenish-white talc, with a silicate of alumina and 

 protoxides of iron and manganese, which serves to render it 

 compact, and probably imparts much of the green color. 



Some specimens also contain actinolite with talc, firmly united, 

 so as to present a close texture, and considerable resistance to 

 fracture. The proportion of chrome iron ore, in crystalline 

 grains, varies in different specimens ; but it is never large 

 enough to seriously interfere with the operations of sawing and 

 polishing. 



As carbonic acid is often found in the analysis of serpentine, 



