mineral

Blue metallic mineral specimen, possibly bornite or chalcopyrite

Bornite (Cu₅FeS₄) or chalcopyrite (CuFeS₂); exact identification requires testing

AI-generated identification · may be incorrect

Small, rough, blue-gray metallic piece with likely sulfide luster; bornite hardness 3–3.25 and chalcopyrite 3.5–4 Mohs, both commonly massive rather than well-crystallized. The blue coloration may be natural iridescence (“peacock ore”) or artificial coating.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Copper-iron sulfides form in hydrothermal veins and magmatic-hydrothermal ore deposits, commonly alongside pyrite and quartz. Specimen age depends on its deposit, ranging from Precambrian to geologically recent.

Uses & applications

Primarily collected as an ore mineral and decorative specimen; copper sulfides are mined for copper. Iridescent pieces are sometimes sold as “peacock ore” for display or low-cost jewelry.

Geological facts

Bornite tarnishes rapidly to purple, blue, and green iridescent colors, while fresh bornite is typically bronze-brown. Chalcopyrite is brassy yellow when fresh and may be artificially treated to produce vivid blue-purple colors.

Field identification & locations

Check for metallic heft, softness, and a dark streak; a copper-colored fresh scratch and lack of glassy translucence support a sulfide mineral. Common localities include Arizona, Montana, Peru, Mexico, and Cornwall.