PHYSIOGRAPHY. 63 



Native Bismuth Native Copper. 



Cleavage, octahedral, perfect. Fracture not observa- 

 ble. Surface rough, often covered with Bismuth-Ochre. 



Lustre metallic. Color silver-white, much inclined to 

 red, subject to tarnish. Streak unchanged. 



Sectile, almost malleable. Hardness=2'0 . . . 2-5. Sp. 

 gr.=9-737. 



Compound Varieties. Imbedded, feathery and arbores- 

 cent shapes. Massive : composition granular, individuals 

 very distinct, though small. 



1. When heated before the blow-pipe, it is volatilized, and leaves a 

 yellow coating upon the charcoal. It is soluble in nitric acid, but the 

 solution yields a white precipitate, if farther diluted. It crystallizes in 

 cubes from fusion. 



2. It commonly occurs in veins in gneiss and clay-slate, and is ac- 

 companied by ores of silver, cobalt, tin, &c. 



3. Its ch'ef localities are several of the Saxon and Bohemian silver 

 and cobalt mines at Schneeberg, Annaberg, Marienberg, Johanngeorgen- 

 stadt, Joachimsthal, &c. It occurs at Fahlun in Sweden, Modum in 

 Norway, in France and England. 



Its only known locality in the U. States, is Monroe, (Conn.) where it 

 occurs in a bed of Quartz, associated with Wolfram, Tungsten, Galena, 

 Blende, &c. 



NATIVE COPPER. Copper Melacone-Metal. 

 Primary form. Cube. 

 Secondary forms. 



1. 2. 



Primary form, with angles truncated. Octahedron. 



Cornwall. Cornwall. 







3. 4. 



Cube, with edges truncated. Dodecahedron. 



Siberia. Cornwall. 



