Native Copper
Houghton County, Michigan

This specimen measures 30cm x 10cm x 9cm, with individual crystals up to 5cm across. The specimen was donated to the collection by Mr. W. A. N. Severance in 1979.

Copper Cu

Native Elements; often with small amounts of arsenic, antimony, bismuth, iron, and silver

Color and Luster: Copper-red; tarnish black, blue, green; metallic; streak copper-red, shiny

Hardness: 2.5-3

Cleavage: None

Fracture: Hackly; ductile and malleable

Crystals: Isometric; usually form cubic and dodecahedral, rarely octahedral; often flattened, elongated, distorted; also scales, plates, lumps, branching aggregates

Copper is one of several elements that commonly occurs in its native state and is extremely abundant in the Keeweenaw Peninsula region of Michigan, where it has been mined for many years. The native copper is associated with a series of ancient, basaltic lava flows and interlayered breccias.

Photo by Mary Sutherland

Descriptions taken from
The Audubon Society Field Guide to North American Rocks and Minerals