mineral
Polished copper nugget
Native copper (Cu)
AI-generated identification · may be incorrectCopper-red to brown, metallic luster with tarnished patches; Mohs hardness 2.5–3, cubic crystal system, and no true cleavage. The smooth triangular shape and polish suggest it has been cut or shaped; identification from the image alone is not certain.
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Physical properties
Copper-red to brown, metallic luster with tarnished patches; Mohs hardness 2.5–3, cubic crystal system, and no true cleavage. The smooth triangular shape and polish suggest it has been cut or shaped; identification from the image alone is not certain.
Formation & geological history
Native copper forms in copper-rich hydrothermal veins and in the oxidized zones of copper deposits, often as irregular masses. Its geological age depends on its source locality.
Uses & applications
Copper is used in electrical wiring, plumbing, alloys, and decorative objects; polished pieces are collected as mineral specimens.
Geological facts
Copper gradually develops brown, red, or green surface tarnish through oxidation; it is malleable and leaves a reddish streak.
Field identification & locations
A metallic reddish color, high malleability, and relatively low hardness help distinguish copper from similarly colored rocks. Major native-copper districts include Michigan’s Keweenaw Peninsula; the specimen’s locality cannot be determined from the photo.
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