8. Oxide of Copper.
A. Black, or Melaconise; a black earthy looking substance found at Chessy and other places. It is deutoxide of copper.
B. Protoxide or red oxide of copper; ziegelerz. Crystallizes in the regular octahedron; specific gravity 5·69; scratches calc-spar; fusible at the blowpipe into the black oxide; and reducible in the smoke of the flame to copper; acted upon by nitric acid with disengagement of nitrous gas; solution is rendered blue by ammonia. Its constituents are oxygen 11·22; copper 88·78. It occurs near Chessy, and upon the eastern slope of the Altai mountains.
9. Phosphate of Copper. Dark green; crystallizes in octahedrons; specific gravity 3·6 to 3·8; scratches calc-spar; yields water with heat; and affords metallic copper with soda flux; acted on by nitric acid. Its constituents are, phosphoric acid 28·7; oxide of copper 63·9; water 7·4. It occurs at the mines of Libethen in Hungary.
10. Pyritous Copper; Kupferkies; a metallic looking substance, of a bronze-yellow colour, crystallizing in octahedrons which pass into tetrahedrons; specific gravity 4·16; fusible at the blowpipe into beads attractable by the magnet, and which afterwards afford copper with a soda flux; soluble in nitric acid; solution is rendered blue by ammonia, and affords an abundant precipitate of iron. Its composition is, sulphur 36; copper 34·5; iron 30·5; being a combined sulphuret of these two metals. This is the most important metallurgic species of copper ores. It occurs chiefly in primitive formations, as among gneiss and mica slate, in veins or more frequently masses in very many parts of the world—Cornwall, Anglesea, Wicklow, &c. It is found among the early secondary rocks, in Shetland, Yorkshire, Mansfeldt, &c. The finest crystallized specimens come from Cornwall, Derbyshire, Freyberg, and Saint Marie-aux-Mines in France.
11. Seleniate of Copper; Berzeline. Is of metallic aspect; silver white; ductile; fusible at the blowpipe into a gray bead, somewhat malleable; is acted upon by nitric acid; consists of selenium 40; copper 64.
12. Sulphate of Copper; Cyanose. Blue; soluble, &c. like the artificial [sulphates], which see.
Brochantite is a subsulphate of copper observed in small crystals at Ekaterinenbourg in Siberia.
13. Sulphuret of Copper; Kupferglanz. Of a steel gray metallic aspect; crystallizes in rhomboids; specific gravity 5·69; somewhat sectile, yet brittle; fusible with intumescence at the blowpipe, and yields a copper bead with soda; soluble in nitric acid; becomes blue with ammonia, but lets fall scarcely any oxide of iron. Its constituents are, sulphur 19; copper 79·5; iron 0·75; silica 1·00. It occurs in small quantities in Cornwall, &c.
The chemical preparations of copper which constitute distinct manufactures are, Blue or Roman vitriol; for which see [Sulphate of Copper]; [Scheele’s green] and [Schweinurth green], [Verditer], and [Verdigris]. See these articles in their alphabetical places.