mineral

Chalcopyrite (Peacock Ore)

Chalcopyrite (CuFeS2)

Hardness: 3.5-4.0 Mohs; Color: Brass yellow (tarnishes to purple, blue, and green); Luster: Metallic; Crystal Structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.1-4.3

Hardness: 3
Color: Brass yellow (tarnishes to purple, blue, and green)
Luster: Metallic

Identified May 9, 2026More mineral →

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Physical properties

Hardness: 3.5-4.0 Mohs; Color: Brass yellow (tarnishes to purple, blue, and green); Luster: Metallic; Crystal Structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.1-4.3

Formation & geological history

Formed in primary sulfide deposits, hydrothermal veins, and by contact metamorphism. It is the most common copper ore mineral and forms in high-temperature environments.

Uses & applications

The primary ore of copper worldwide. While high-quality iridescent specimens are valued by collectors, mass-mined material is used for industrial copper production.

Geological facts

When naturally tarnished or chemically treated to enhance its iridescence, it is commonly marketed as 'Peacock Ore.' It is often confused with Bornite, though Chalcopyrite has a more golden-yellow base color.

Field identification & locations

Identify in the field by its brassy color, greenish-black streak, and brittle tenacity. Found globally in copper mimes, notably in Chile, Peru, Canada, and the United States (Arizona/Montana).