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DESCRIPTIVE MINERALOGY. 



ORDER VI. COPPER. 



This order includes the following species, viz : 



1. Native Copper. 



2. Red Copper ore. 



3. Vitreous Copper. 



4. Copper Pyrites. 



5. Green Malachite. 



6. Azurite. 



NATIVE COPPER. 



Ciiivre Natif. Hauy. — Native Copper. Ckavchnd, Phillrps, Shepard and Tkomsmi. — Octahedral Copper. 

 Jameson. — Octaedrisclies Kupfcr. Mofis. — Cuivre. Bcudunt. 



^'S- ^'^- Description. Colour copper-red. Streak shining, but unchanged 



in colour. It occurs regularly crystallized ; also capillary, dendritic, 

 in thin plates and massive. Primary form the cube, Fig. 502 ; but it 

 is also found in octahedrons and in compound crystals. Cleavage 

 none. Fracture hackly. Lustre metallic. Ductile. Opaque. Hard- 

 ness from 2.5 to 3.0. Specific gravity from 8.50 to 8.90. Before 

 the blowpipe, it melts easily ; and on cooling, is covered with a coat 

 of oxide. It is soluble in nitric acid, to which it gives a green colour. 

 Anmionia added to this solution in suiEcient quantity, produces a fine blue transparent solu- 

 tion. 



Geological Situation. This mineral occurs in granite, gneiss and mica slate, primitive 

 limestone and serpentine ; also in secondary limestone and sandstone. 



LOCALITIES. 



Washington County. Native copper has been found in this county, but the precise loca- 

 lity is as yet unknown. 



Detached masses of native copper of various sizes occur throughout the United States, 

 especially in Michigan, Illinois, Missouri, and the territory of Iowa. Similar masses, some- 

 times of large size, are found in the soil in various parts of New- Jersey, where thin sheets of 

 nearly pure native copper are frequently observed traversing the red sandstone in the form of 

 narrow veins. These sheets closely resemble the copper of cementation, and they are often 

 covered on either side by a coating of the oxide or carbonate of copper.* 



Native copper also abounds in the greenstone trap and red sandstone formations of Connec- 

 ticut and Massachusetts, and in similar situations in Michigan and Iowa. 



* See a paper by the author, in the American Journal of Science. XXXVI. 107. 



