296 



HETALS, 



curs in slender aggregated prisms, of a -dork ead-gray color. Anoihei 

 containing also arsenic, is called antiraonial copper glance. 



Tennantite is a compound of copper, iron, sulphur, and arsenic. It 

 occurs in dodecahedral crystals, brilliant, with a dark lead-gray color 

 and reddish-gray streak. From the Cornish mines near Redruth and 

 St. Day. Domeykite is arsenical copper. 



Selenid of Copper, is a silver-white ore, affording the horse-radish 

 odor of selenium before the blowpipe. It contains 64 per cent, of cop- 

 per. From Skrikerum, Sweden. * 



RED COPPER ORE. 



Monometric. In regular octahedrons, and modified forms 

 of the same. Cleavage octahedral, Also massive, and 

 1 sometimes earthy. 2 



Color deep red, of various 

 shades. Streak brownish-red. 

 Luster adamantine or submetal- 

 lic ; also earthy. Subtranspa- 

 rent to nearly opaque. Brittle. 

 H=3-5— 4. Gr=6. 

 Composition : copper 88 '8, oxygen 1 1 *'2. Before the blow- 

 pipe, on charcoal, it yields a globule of copper. Dissolves 

 in nitric acid. The earthy varieties have been called tile 

 ore, from the color. 



Dif. From cinnabar it differs in not being volatile before 

 the blowpipe ; and from red iron ore, in yielding a bead of 

 copper on charcoal, and copper reactions. 



Ohs. Occurs with other copper ores in the Bannat, Thur- 

 ingia, Cornwall, at Chessy near Lyons, in Siberia, and Bra- 

 zil. The octahedrons are often green, from a coating of 

 malachite. 



In the U. States, it has been observed crystallized and 

 massive, at Schuyler's, Somerville, and the Flemington cop- 

 per mines, N. J. ; also near New Brunswick, N. J. ; at 

 Bristol, Ct. ; also near Ladenton, Rockland county, N. Y. 



Black Copper. Tenorite. An oxyd of copper, occurring 

 as a black powder and in dull black masses, and botryoidal 

 concretions, in veins or along with other copper ores- From 

 Cornwall, and also the Vesuvian lavas. It is an abundant 

 ore in some of the copper mines of the Mississippi valley 

 and yields 60 to TO per cent, of copper. It results from the 



fthat is the crystallization of red copper ore I Of what does it eon 

 :: * How does it differ from cinnabar and re I iron ore? 



