mineral
Chalcopyrite
CuFeS2 (Copper Iron Sulfide)
Hardness: 3.5-4 on the Mohs scale. Color: Brass yellow, often with an iridescent tarnish showing purple, blue, and green hues (peacock ore). Luster: Metallic. Crystal Structure: Tetragonal. Streak: Greenish-black. Specific Gravity: 4.1-4.3.
- Hardness
- 3
- Luster
- Metallic
- Streak
- Greenish-black
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Physical properties
Hardness: 3.5-4 on the Mohs scale. Color: Brass yellow, often with an iridescent tarnish showing purple, blue, and green hues (peacock ore). Luster: Metallic. Crystal Structure: Tetragonal. Streak: Greenish-black. Specific Gravity: 4.1-4.3.
Formation & geological history
Forms in hydrothermal veins, contact metamorphic deposits, and igneous rocks associated with copper-bearing magmas.
Uses & applications
Primary ore of copper; also collected as mineral specimens and sometimes sold under the trade name 'peacock ore' (though natural tarnish can be enhanced with acid).
Geological facts
Often confused with pyrite due to its golden color and similarity to 'fool's gold,' but chalcopyrite is softer and has a distinctive greenish-black streak and often an iridescent tarnish.
Field identification & locations
Identify by its brassy yellow color, metallic luster, softness (can be scratched with a knife), and greenish-black streak. Commonly found worldwide in major copper-producing regions.
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