Mineral Guide > Ores > Copper and Lead Ore

Copper and Lead Ore

Native copper scarcely needs a description. Its occurrence in its free state provides an interesting subject of conjecture. Briefly stated, the question of origin is whether the copper was set free by the decomposition of silicates or was in the form of a sulphide in the rock. The chief region of occurrence of native copper is the Lake Superior district.

The ore chalcocite, sometimes called copper glance, has a metallic luster, often tarnished green or blue. It is commonly lead-gray and rather soft. Its streak is a blackish lead-gray.

Chalcopyrite is a sulphide of copper and iron combined. When copper is much in predominance the color of the ore is golden yellow. The streak is dark green. The mineral is harder than chalcocite, but less hard than pyrite, being easily scratched with a knife. Both chalcocite and chalcopyrite frequently occur in silver-bearing rocks.
Lead occurs in nature chiefly in the forms of the sulphide, galenite or galena ; the sulphate, anglesite, and the carbonate, and cerussite.

Galena is lead-gray, quite soft, and frequently occurs in a coarsely crystalline condition, the crystals often being cubical. The luster is metallic, hence a superficial examination of a specimen might result in mistaking the mineral for the copper ore, chalcopyrite, already described. The streak will serve to identify any specimen, however, it being a lead-gray of much lighter shade than that of chalcocite.

Anglesite and cerussite are far less abundant than galena. The former varies from white through gray to yellow and has a resinous luster.

Cerussite is white or gray, resembling anglesite, and has a brilliant, vitreous luster. Both minerals, like galena, are soft and easily scratched with a knife.

Anglesite picture
Cerussite coating Galenite picture
Chalcocite picture
Cholcopyrite picture
Galenite picture
Native Copper picture