mineral

Chalcopyrite (Peacock Ore)

Chalcopyrite (CuFeS2)

Hardness: 3.5-4 Mohs; Color: Brass yellow (tarnishes to iridescent blues, purples, and yellows); Luster: Metallic; Crystal Structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.1-4.3

Hardness: 3
Luster: Metallic

Identified June 30, 2026More mineral →

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Physical properties

Hardness: 3.5-4 Mohs; Color: Brass yellow (tarnishes to iridescent blues, purples, and yellows); Luster: Metallic; Crystal Structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.1-4.3

Formation & geological history

Formed in hydrothermal veins, contact metamorphic deposits, and as a primary mineral in igneous rocks. It is found in deposits ranging from Precambrian to Cenozoic ages.

Uses & applications

Major ore of copper. Used in the production of electrical wiring, plumbing, and electronics. Natural iridescent specimens (Peacock Ore) are highly valued by collectors and used in ornamental jewelry.

Geological facts

Known as 'Peacock Ore' when tarnished, it is often confused with Pyrite (Fool's Gold) but is softer and has a deeper yellow color. It is the most abundant copper-bearing mineral in the crust.

Field identification & locations

Identified by its metallic brass color and low hardness (can be scratched by a knife). Commonly found in copper mines worldwide, notably in Arizona (USA), Chile, and Cornwall (UK). Collectors should look for vibrant iridescence.