mineral

Copper-bearing rock, likely native copper in matrix

Native copper (Cu), possibly with cuprite/iron-rich matrix

AI-generated identification · may be incorrect

Small irregular metallic specimen with reddish-brown to coppery color and dull metallic luster; native copper has Mohs hardness 2.5–3, cubic crystal structure, no cleavage, and specific gravity about 8.9. The photograph is insufficient to confirm composition or distinguish it from copper-rich slag.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Native copper forms in hydrothermal veins and oxidized zones of basaltic and sedimentary copper deposits, commonly in Precambrian to younger rocks. Associated cuprite, malachite, chalcocite, and iron oxides may occur.

Uses & applications

Collected as a mineral specimen and historically mined for electrical wiring, plumbing, roofing, and alloys; the pictured piece is probably too small for industrial use or jewelry.

Geological facts

A diagnostic feature is a reddish metallic streak and the ability to bend or deform rather than fracture like most silicate minerals. Copper may develop green carbonate coatings through weathering.

Field identification & locations

Common localities include Michigan’s Keweenaw Peninsula, Arizona, Cornwall, and Chile; test cautiously with a streak plate and magnet—copper is nonmagnetic. Definitive identification requires hardness, streak, density, or elemental testing.