mineral

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Hardness: 3.5-4 (Mohs); Color: Brass yellow, often with iridescent purple, blue, or green tarnish; Luster: Metallic; Crystal Structure: Tetragonal; Cleavage: Poor/Indistinct; Specific Gravity: 4.1-4.3

Hardness: 3
Luster: Metallic

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, contact metamorphic deposits, and as a primary mineral in igneous rocks via magmatic segregation. Found throughout most geological ages where sulfide mineralization occurs.

Uses & applications

Primary ore of copper; occasionally used as an ornamental stone or in inexpensive jewelry when iridescent (often sold as 'Peacock Ore'). Important for industrial copper production for wiring and alloys.

Geological facts

Often confused with gold or pyrite (Fool's Gold). Unlike gold, it is brittle and will crush rather than flatten. The name comes from the Greek words 'chalkos' (copper) and 'pyrites' (strike fire).

Field identification & locations

Identify by its metallic brass color and greenish-black streak. It is softer than pyrite (which cannot be scratched by a copper penny, whereas chalcopyrite can). Found globally in massive deposits in places like Chile, Peru, Canada, and the USA.