mineral

Chalcopyrite in Quartz (Gold Ore Matrix)

CuFeS2 (Chalcopyrite) with SiO2 (Quartz)

Hardness: 3.5-4 (Chalcopyrite), 7 (Quartz); Color: Brass-yellow (mineral), White/Grey (matrix), Red/Brown (hematite staining); Luster: Metallic; Crystal Structure: Tetragonal; Specific Gravity: 4.1-4.3

Hardness: 3
Luster: Metallic

Identified May 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins and through magmatic segregation. These specimens typically form when hot, mineral-rich fluids circulate through fractures in igneous or metamorphic host rocks, precipitating sulfides and silica.

Uses & applications

Major ore for copper extraction; high-grade specimens are valued by mineral collectors for their colorful tarnish (peacock ore) and presence of associated gold.

Geological facts

Often mistaken for real gold by novice prospectors, giving it the nickname 'Fool's Gold', though it is more brassy and softer than pyrite. It is the most common copper mineral in the crust.

Field identification & locations

Identify by its metallic brass luster against a dull white or blue-grey chalcedony/quartz background. Commonly found in copper-producing regions like Arizona, Montana, and Australia.

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