292 METALS. 



COPPER GLANCE. VITREOUS COPPER ORE. 



Trimetiic. Cleavage parallel to the faces of a right rhom. 

 bic prism, but indistinct. IVt : M=119' 35'. Secondary 

 forms, variously modified rhombic prisms. Also in com- 

 pound crystals like arragonite ; often massive. 



Color and streak blackish lead-gray, often tarnished blue 

 r green. Streak sometimes shining. H=2 , 5— 3. Gr= 

 •5—5-8. 



Composition : sulphur 20*6, copper 77*2, iron 1*5. Be- 

 ore the blowpipe it gives off fumes of sulphur, fuses easily 

 n the external flame, and boils. After the sulphur is driven 

 off, a globule of copper remains. Dissolves in heated nitric 

 acid, with a precipitation of the sulphur. 



Dif. The vitreous copper ore resembles vitreous sil- 

 ver ore ; but the luster of a surface of fracture is less bril- 

 liant, and they afford different results before the blowpipe. 

 The solution made by putting a piece of the ore in nitric 

 acid, covers an iron plate (or knife blade) with copper, while 

 a similar solution of the silver ore covers a copper plate 

 with silver. 



Obs. Occurs with other copper ores in beds and veins. 

 At Cornwall, splendid crystallizations occur. Siberia, Hesse, 

 Saxony, the Bannat, Chili, &c, afford this ore. 



In the United States, a vein affording fine crystallizations 

 occurs at Bristol, Conn. Other localities are at Wolcott 

 ville, Simsbury, and Cheshire, Conn. ; at Schuyler's Mines, 

 and elsewhere, N. J. ; in the U. S. copper mine district, 

 Blue Ridge, Orange county, Virginia ; between New Mark- 

 et and Taneytown, Maryland ; and sparingly i\t the copper 

 mines of Michigan and the Western states; also at some 

 mines north of Lake Huron. 



Blue Copper is a dull blue-black massive mineral. Gi—38 — . It 

 contains 65 per cent, of copper. It is named Covelline. 



Hurrisite is a copper glance, with cubic cleavage, from Canton 

 mine, Ga., probably a pseudomorph after Galena. 



copper pyrites. — SulpJiuret of^ Copper and Iron. 

 Dimetric. Crystals tetraliedral or octahedral ; sometimes 



What are the physical characters of vitreous copper ] its constitution 

 nd chemical characters 1 How does it differ from silver ores ] 



