mineral

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

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

Hardness: 3
Color: Brass yellow to iridescent
Luster: Metallic

Identified June 14, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in hydrothermal veins, contact metamorphic deposits, and as a primary mineral in igneous rocks. Present in large sulfide deposits worldwide.

Uses & applications

The most important ore of copper. Also used as a collector specimen and occasionally for sulfur production.

Geological facts

Often confused with gold, it is known as 'Fool\'s Gold' alongside pyrite. Exposure to air can cause it to tarnish into a rainbow-like spectrum of colors, known as 'Bornite' or 'Peacock Ore.'

Field identification & locations

Identify by its brassy yellow color and relatively low hardness (can be scratched by a steel nail, unlike pyrite). Found in copper mines globally, including Peru, Chile, and the USA.