mineral

Chalcopyrite in Matrix

Chalcopyrite (CuFeS2)

Hardness: 3.5-4.0; Color: Brass yellow to golden; Luster: Metallic; Crystal Structure: Tetragonal; Streak: Greenish-black; Cleavage: Poor/Indistinct; Specific Gravity: 4.1-4.3

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

Identified April 20, 2026More mineral →

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Physical properties

Hardness: 3.5-4.0; Color: Brass yellow to golden; Luster: Metallic; Crystal Structure: Tetragonal; Streak: Greenish-black; Cleavage: Poor/Indistinct; Specific Gravity: 4.1-4.3

Formation & geological history

Forms primarily in hydrothermal veins and via magmatic segregation in igneous rocks. Often found in porphyry copper deposits and sulfide-rich metamorphic environments.

Uses & applications

Primary ore of copper; occasionally used as a minor source of gold or silver if contained as impurities. High-quality iridescent specimens are popular for mineral collectors.

Geological facts

Also known as 'Peacock Ore' when it tarnishes to a blue/purple iridescent color. It is the most abundant copper-bearing mineral in the world and has been mined for thousands of years.

Field identification & locations

Identify by its 'fool's gold' appearance but with a deeper yellow tone than pyrite and lower hardness (it can be scratched by a knife, unlike pyrite). Look for it in quartz veins and near copper mine tailings.