Rock Identifier
Chalcopyrite (Copper Iron Sulfide (CuFeS2)) — mineral
mineral

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Hardness: 3.5 to 4 on the Mohs scale; Color: Brass-yellow, often with an iridescent tarnish showing purple, blue, and green hues; Luster: Metallic; Crystal Structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.1 to 4.3

Hardness
3
Luster
Metallic
Identified More mineral
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Physical properties

Hardness: 3.5 to 4 on the Mohs scale; Color: Brass-yellow, often with an iridescent tarnish showing purple, blue, and green hues; Luster: Metallic; Crystal Structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.1 to 4.3

Formation & geological history

Formed mainly in hydrothermal veins, associated with high-temperature ore deposits, and in sedimentary and metamorphic rocks worldwide.

Uses & applications

Primary ore of copper, occasionally cut into cabochons or collected as mineral specimens.

Geological facts

Often referred to as 'peacock ore' due to its vibrant tarnish when exposed to weathering or acid. It is frequently confused with pyrite, but is softer and has a deeper yellow or iridescent color.

Field identification & locations

Identify by its brass-yellow color, metallic luster, lower hardness than pyrite (can be scratched with a knife), and distinctive peacock-like tarnish. Found globally in copper-rich mining regions.