coprER. 261 



copper 69-5, sulphur 19, iron 7*5, oxygen 4. It is found with 

 several of the other ores of copper, in Cornwall, Norway, Saxony, 

 and other countries. 



Sp. 5. Grey Sulphuret of Copper. Pl. XXXV. fig. 2. — 

 Fahlerz, Werner ; Cuivre gris, Hauy. — Its colours are steel-grey, 

 lead-grey, or iron -black. It occurs massive, disseminated, and 

 crystalized, in small tetrahedrons, variously truncated, fig. c, d, e j 

 also in rhomboidal dodecahedrons. It is brittle ; the fracture is 

 uneven or imperfectly conchoidal, with a shining or metallic 

 lustre. It yields to the knife. The specific gravity is 4-5. Before 

 the blow-pipe it gives out arsenical vapours, decrepitates, and melts 

 into a brittle grey globule. It varies greatly in its chemical com- 

 position, one variety, according to Chenevix, yields copper 52, 

 iron 33, sulphur 14. It is found in Cornwall, and various other 

 countries. 



Sp. 6. Red Copper or Ruby Copper. Pl. XXXV. fig. 3.— 

 Rothkupfererz, Werner; Cuivre oxide rouge, Hauy ; Octaedris- 

 ches Kupfer erz, Mohs. — The colour of this mineral is dark cochi- 

 neal red of various shades, passing into lead-grey or brown. It 

 occurs massive and crystalized in the form of the octahedron, 

 which is the primitive form ; also in cubes and rhomboidal dode- 

 cahedrons. The crystals are small and transparent or translucent, 

 externally splendent, sometimes iridescent or superficially tar- 

 nished, with a metallic lustre. The structure of the crystals is 

 laminar ; the cross fracture is uneven, sometimes conchoidal. It 

 yields easily to the knife, and gives a brownish streak. The specific 

 gravity is from 5*6 to 6-0. It dissolves with effervescence in nitric 

 acid. Before the blow-pipe on charcoal it is easily reducible to 

 the metallic state. It consists of copper 88*5, oxygen 115. Che- 

 nevix. This species is found in veins in primitive, transition, and 

 secondary rocks, associated with other ores of copper, in Cornwall, 

 Germany, Siberia, Norway, and other countries. 



Compact. Red Copper Ore is of a dark red colour, with a semi- 

 metallic lustre. It occurs in amorphous masses, disseminated, and 

 also reniform. It is opaque or translucent on the edges ; and the 

 fracture is even or granular. 



Capillary Red Copper Ore, consists of very minute capillary 



