PHYSIOGRAPHY. 



Serpentine. 



179 



Secondary form. 



Fig. 391. 



M 



o on o 

 d on d 

 a on a 1 

 a on a 

 a on d 



128 31' 

 97 33 

 139 34 

 105 26 

 134 13 



Cleavage. Traces of, parallel with M and J, apparent 

 only in a strong light. Fracture flat conchoidal, splintery, 

 uneven. Surface almost dull, very little glistening, but 

 rather even. 



Lustre resinous, indistinct, low degrees of intensity. Co- 

 lor dark blackish green and leek-green, seldom lighter 

 shades of oil-green and siskin-green colors, none of them 

 being bright : they pass into yellowish-grey. Streak white, 

 acquires some lustre. Translucent . . . opake. 



Sectile. Hardness = 3-0. Sp. gr.=2-507, of a green- 

 ish black crystallized variety; =2*56, of an oil-green, 

 translucent one. 



Compound Varieties. Massive : composition granular, 

 impalpable. Varieties of this kind present also, red, brown, 

 black, yellow, and grey colors, in different veined, spotted 

 and other delineations. The purer varieties sometimes 

 possess an indistinctly slaty structure. 



