mineral
Native copper
Copper (Cu), often with malachite, cuprite, or matrix minerals
AI-generated identification · may be incorrectTypically Mohs hardness 2.5–3, metallic luster, copper-red to brown tarnished color, and a dense, malleable, irregular form; the greenish areas may be copper oxidation products. Native copper is cubic (isometric) in crystal structure but commonly occurs as massive or nugget-like pieces.
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Physical properties
Typically Mohs hardness 2.5–3, metallic luster, copper-red to brown tarnished color, and a dense, malleable, irregular form; the greenish areas may be copper oxidation products. Native copper is cubic (isometric) in crystal structure but commonly occurs as massive or nugget-like pieces.
Formation & geological history
Forms when copper-rich hydrothermal fluids deposit metal in fractures, cavities, and volcanic or sedimentary rocks; major deposits are associated with Precambrian terrains, including Michigan’s Keweenaw Peninsula. The specimen appears rounded and possibly polished or naturally water-worn.
Uses & applications
Used mainly as an ore and historically for electrical wiring, plumbing, tools, and ornaments; attractive native-copper specimens are collected. It is not typically used as a gemstone.
Geological facts
Copper’s distinctive reddish metallic color and unusually high density help distinguish it from most rocks. Green or blue coatings commonly represent malachite, azurite, or other secondary copper minerals.
Field identification & locations
Identify by copper-red color, metallic sheen, softness, heavy feel, and possible green oxidation; a streak or conductivity test can help, but avoid damaging valuable specimens. Common localities include Michigan, Arizona, Chile, and the Democratic Republic of the Congo.
