322 APPENDIX. 



CHROME ORE. 



CHRYSOCOLLA. 



It appears to be abundant at Keweena Point, Lake Superior, in con- 

 nexion with the trap and sandstone formation. 



COBALTIC GALENA. 



In minute moss-like groups of crystals, and massive. Cleavable. 

 Lustre metallic. Color lead-grey, inclining to blue. Opake. Soils 

 a little. 



When heated before the blow-pipe, it splits into fragments, and com- 

 municates a smalt-blue color to borax. 



Analysis. 



By DuMENiL. 



Lead ....... 62-89 



Arsenic* . t . . . . . 22-47 



Sulphur ....... 0-47 



Iron . ...... 2-11 



Cobalt ....... 094 



Arsenical pyrites ...... 1-44 



It occurs in a vein of clay-slate, in one of the Clausthal mines in the 

 Hartz. 



COBALT PYRITES. Cobaltic Eruthleucone- 

 Py rites. 



Primary form. Regular octahedron ? 



Massive; composition granular . . . impalpable. Individ- 

 uals indistinctly cleavable. Fracture conchoidal, uneven. 



Lustre metallic. Color pale steel-grey, rarely present- 

 ing a reddish tinge. 



Hardness =5-0... 6-0. 



1. Heated before the blow-pipe, it decrepitates briskly. Upon char- 

 coal, it emits the odor of sulphurous acid, and melts into a magnetic glob* 

 ule, which 13 steel-grey on the surface, and bronze-yellow within, 



