^3 
seen products resulting from the treatment of some of the ores 
and charts showing processes of extraction of the metals. 
Under each group are placed first, type specimens of the dif- 
ferent ores of the metal arranged in order of their richness ; then 
specimens of ores which illustrate the different localities produc- 
ing them, these being arranged in geographical order. Specimen 
labels show the mineral of the ore and the amount of metal con- 
tained where this is known. It should be remembered that many 
of the ores produce more than one metal, in which case the speci- 
men is placed in the group of the predominating metal. 
COPPER. 
Case 1. — The copper bearing minerals, arranged in order of 
their richness ; the native metal, this being the character of most 
of the ore from the Lake Superior mines ; the red oxide, cuprite, 
88 per cent, of copper; the black oxide, tenor ite^ 8o per cent.; the 
black sulphide, chalcocite, 8o per cent. ; the green carbonate, mala- 
chite, 57 per cent. ; the blue carbonate, azurite, 55 per cent; the 
purple sulphide, bornite, 55 per cent. ; the gray sulphide, tetrahed- 
rite, about 50 per cent. ; the bluish green silicate, chrysocolla, 36 
per cent. ; and the brass yellow sulphide, chalcopyrite, 34 per 
cent. 
Case 2, — Copper ores. Eastern States and Michigan. 
Case 3, — Copper ores. South America and West Indies. 
Case 4, Rear, — Copper ores. New South Wales. 
Case 5, Rear. — Copper ores, Germany. 
Cases 4 and 5, Front. — Copper ores, New Mexico and 
Arizona. 
Case A. — Specimens illustrating successive stages in the pro- 
cess of copper smelting and separation. 
Case B. — Specimens of electrically deposited copperillustrat- 
ing the electric mode of refining. A very complete collection of 
the native copper and associated minerals of Keweenaw Point, 
Michigan. 
On the adjacent walls are charts showing courses of treatment 
of copper ores practiced by different smelters. Below them are 
large masses of copper ores. 
