mineral

Peacock Ore

Bornite (Cu5FeS4) or Chalcopyrite (CuFeS2) with iridescent tarnish

AI-generated identification · may be incorrect

Hardness: 3-3.5 on Mohs scale. Color: Initially bronze-brown, tarnishing to iridescent blues, purples, and greens. Luster: Metallic. Crystal Structure: Orthorhombic. Cleavage: Poor.

Hardness: 3-3
Luster: Metallic

Identified May 19, 2026More mineral →

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Physical properties

Hardness: 3-3.5 on Mohs scale. Color: Initially bronze-brown, tarnishing to iridescent blues, purples, and greens. Luster: Metallic. Crystal Structure: Orthorhombic. Cleavage: Poor.

Formation & geological history

Formed in copper ore deposits, typically in hydrothermal veins, contact metamorphic zones, or as a secondary mineral in enriched zones of copper deposits.

Uses & applications

Major ore of copper. Widely sold as ornamental specimens for collectors and in 'metaphysical' shops due to its vibrant colors.

Geological facts

Natural Bornite develops its peacock-like tarnish organically upon exposure to air, but many specimens in the market are actually Chalcopyrite that has been acid-washed to force the iridescent oxidation.

Field identification & locations

Identify in the field by its distinctive iridescent tarnish and metallic gray-black streak on a porcelain plate. Commonly found in copper mines globally, notably in Arizona, Montana, and Mexico.