mineral

Peacock ore (bornite/chalcopyrite), likely treated

Bornite, Cu₅FeS₄, and/or chalcopyrite, CuFeS₂

AI-generated identification · may be incorrect

Irregular metallic sulfide specimen with vivid blue, purple, green, and gold tarnish; typically Mohs 3–4, opaque, metallic luster, massive rather than visibly crystalline, with poor cleavage. The intense iridescence is commonly enhanced by acid treatment or oxidation.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Copper-iron sulfides form in hydrothermal veins and disseminated porphyry-copper deposits, chiefly during igneous and metamorphic activity; specimens may be geologically millions to billions of years old. Common sources include Mexico, Peru, the United States, and Kazakhstan.

Uses & applications

Collected as a decorative mineral and teaching specimen; bornite and chalcopyrite are important copper ores, though this colorful material is generally not economically processed. It is rarely used in jewelry because it is soft and tarnishes easily.

Geological facts

“Peacock ore” is a commercial name rather than a single mineral; naturally iridescent bornite is less common than artificially tarnished chalcopyrite. Avoid prolonged skin contact with treated pieces and do not ingest or grind them.

Field identification & locations

Identify by metallic heft, low hardness, opaque sulfide interior, and rainbow tarnish; a streak test is usually dark gray to black. Estimated value: $5–$30 for a hand-sized common specimen, up to $50–$100 for attractive natural or well-prepared pieces.