PHYSIOGRAPHY. 



Copperas. 



145 



3. It was discovered in the Condurrow mine at Cornwall. 



CONITE. (See Dolomite.) 



COPPERAS. Herni-Prismatic Vitriol-Salt, 

 MOHS. 



Primary form. Oblique rhombic prism. M on M'= 

 82 20'. P on M or M' = 99 20'. 



Secondary forms. The primary is almost invariably af- 

 fected by slight replacements of the acute and obtuse solid 

 angles, as well as of the acute and obtuse terminal edges.* 

 More rarely the lateral edges are removed also. 



Fig. 148. 



Cleavage, parallel to P perfect ; that parallel to M less 

 perfect. Fracture conchoidal. Surface generally smooth. 



Lustre vitreous. Color, several shades of green, pass- 

 ing into white. Streak white. Semi-transparent., .trans- 

 lucent. A faint bluish opalescence sometimes observable 

 parallel to the faces M. 



Rather brittle. Hardness =2-0. Sp. gr. =1-832 of a 

 variety containing about 0*1 of sulphate of copper. Taste 

 sweetish astringent and metallic. 



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