PHYSIOGRAPHY. 



Electric Calamine. 



179 



ELECTRIC CALAMINE. Prismatic Zinc- 

 Baryte. MOHS. 



Primary form. Right rhombic prism. M on M=102 

 35'. 



Secondary form. 



Fig. 165. 



M on M 

 M on a 

 a on h 

 a on c or e 

 c on c' 



102 30' 



132 35 



128 40 



115 00 



126 36 J 



Cleavage, parallel with the primary lateral planes, per- 

 fect ; traces of cleavage parallel with the terminal planes. 

 Fracture uneven. Surface of lateral planes streaked par- 

 allel with their common intersections. The rest of the 

 faces generally smooth, sometimes rounded. 



Lustre vitreous, inclining to pearly, sometimes to ada- 

 mantine upon curved faces of crystallization. Color white, 

 prevalent : occasionally blue, green, yellow or brown. 

 Streak while. Transparent . . . translucent. 



Brittle. Hardness = 5-0. Sp. gr. = 3-379, crystals 

 from Rossegg in Carinthia. 



Compound Varieties. Globular, botryoidal shapes : sur- 

 face drusy. Massive : composition either granular or co- 

 lumnar ; the former of them often impalpable and strongly 

 coherent, and then the fracture becomes uneven ; the lat- 

 ter straight and divergent. 



