mineral

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Hardness: 3.5-4.0 Mohs; Color: Brass-yellow, often with an iridescent tarnish; Luster: Metallic; Crystal Structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.1-4.3

Hardness: 3
Color: Brass-yellow, often with an iridescent tarnish
Luster: Metallic

Identified June 28, 2026More mineral →

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Physical properties

Hardness: 3.5-4.0 Mohs; Color: Brass-yellow, often with an iridescent tarnish; 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 via magmatic segregation. Found throughout various geological ages across the globe.

Uses & applications

Primary ore of copper. Occasionally used in jewelry as 'Peacock Ore' when treated. Important collector specimen for mineralogy.

Geological facts

Often confused with gold or pyrite, it is known as 'Fool\'s Gold'. It becomes magnetic when heated. It is the most important source of copper globally.

Field identification & locations

Identify by its brassy color, relative softness compared to pyrite (it can be scratched by a knife), and greenish-black streak. Found in major mining districts like those in Chile, Canada, and Australia.