mineral
Bornite (Peacock Ore)
Bornite (Cu5FeS4)
AI-generated identification · may be incorrectHardness: 3 on Mohs scale; Color: Brownish-bronze, tarnishing to iridescent purple/blue/green; Luster: Metallic; Crystal Structure: Orthorhombic; Cleavage: Poor; Specific Gravity: 5.06-5.08
- Hardness
- 3 on Mohs scale
- Color
- Brownish-bronze, tarnishing to iridescent purple/blue/green
- Luster
- Metallic
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Physical properties
Hardness: 3 on Mohs scale; Color: Brownish-bronze, tarnishing to iridescent purple/blue/green; Luster: Metallic; Crystal Structure: Orthorhombic; Cleavage: Poor; Specific Gravity: 5.06-5.08
Formation & geological history
Formed in hydrothermal veins, contact metamorphic zones, and as a primary mineral in copper deposits. It is often found in the supergene enrichment zone of copper ore bodies.
Uses & applications
Important ore of copper; highly popular as a decorative specimen for collectors and teaching tools in geology.
Geological facts
Often called 'Peacock Ore' because its iridescent tarnish resembles a peacock's feathers. While true Bornite naturally tarnishes, sometimes Chalcopyrite is treated with acid to mimic this effect.
Field identification & locations
Identified by its distinctive purple-blue tarnish, low hardness (can be scratched by a copper coin), and dark gray-black streak. Common in copper mines in Arizona and Montana (USA), Cornwall (UK), and Chile.
