mineral

Chalcopyrite in Gossan

Chalcopyrite (CuFeS2) in a Limonite-rich Gossan matrix

AI-generated identification · may be incorrect

Hardness: 3.5-4 (mineral), variable (matrix); Color: Brass-yellow (chalcopyrite), green (malachite staining), rusty brown/black (gossan); Luster: Metallic to dull; Crystal structure: Tetragonal.

Hardness: 3
Luster: Metallic to dull

Identified July 14, 2026More mineral →

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Physical properties

Hardness: 3.5-4 (mineral), variable (matrix); Color: Brass-yellow (chalcopyrite), green (malachite staining), rusty brown/black (gossan); Luster: Metallic to dull; Crystal structure: Tetragonal.

Formation & geological history

Forms in hydrothermal veins and sulfide ore deposits. This specimen shows a 'gossan' or 'iron hat' surface, which is the oxidized upper part of an ore deposit where sulfide minerals have weathered into oxides, carbonates, and sulfates.

Uses & applications

Major ore of copper; used for copper extraction in industry and as a mineral specimen for collectors.

Geological facts

Chalcopyrite is often confused with gold but is much harder and more brittle. The green staining present on this rock is likely malachite, a common oxidation product of copper minerals.

Field identification & locations

Identify by the brassy metallic flecks and presence of rusty oxidation or green malachite staining. Commonly found near copper mines or tectonic plate boundaries. Collectors should look for the metallic sheen against dark, weathered rock.