mineral
Polished native copper
Native copper (Cu), likely with cuprite/tenorite oxidation products
AI-generated identification · may be incorrectMetallic to submetallic luster; copper-brown to dark tarnished surface with reddish-orange patches and possible bluish-green oxidation. Mohs hardness 2.5–3, cubic crystal system, no cleavage, and very high specific gravity (~8.9); the irregular holes may reflect natural cavities or corrosion.
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Physical properties
Metallic to submetallic luster; copper-brown to dark tarnished surface with reddish-orange patches and possible bluish-green oxidation. Mohs hardness 2.5–3, cubic crystal system, no cleavage, and very high specific gravity (~8.9); the irregular holes may reflect natural cavities or corrosion.
Formation & geological history
Formed hydrothermally when copper-bearing fluids precipitated elemental copper in fractures and cavities, commonly in basaltic volcanic rocks; deposits range from Precambrian to younger ages. This specimen appears polished or naturally water-worn and oxidized.
Uses & applications
Used primarily as a mineral specimen and occasionally for educational displays; copper ore is smelted for electrical wiring, plumbing, alloys, and industry, but this piece has little practical metal value.
Geological facts
Native copper is unusually malleable and electrically conductive. Its dark coating can include cuprite (Cu₂O), tenorite (CuO), and other secondary copper minerals.
Field identification & locations
Confirm with a copper streak or scratch test, malleability, and unusually high heft; distinguish from metallic slag by its natural-looking copper oxidation and softness. Important localities include Michigan’s Keweenaw Peninsula, Arizona, Chile, and the Ural Mountains.
