mineral
Bornite
Cu5FeS4 (Copper Iron Sulfide)
Hardness: 3 (Mohs Scale), Color: Brown to copper-red on fresh surfaces; tarnishes to iridescent blues, purples, and reds, Luster: Metallic, Crystal Structure: Orthorhombic (pseudo-cubic)
- Hardness
- 3 (Mohs Scale), Color: Brown to copper-red on fresh surfaces
- Color
- Brown to copper-red on fresh surfaces
- Luster
- Metallic, Crystal Structure: Orthorhombic (pseudo-cubic)
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Physical properties
Hardness: 3 (Mohs Scale), Color: Brown to copper-red on fresh surfaces; tarnishes to iridescent blues, purples, and reds, Luster: Metallic, Crystal Structure: Orthorhombic (pseudo-cubic)
Formation & geological history
Found primarily in copper ore deposits, forming in hydrothermal veins, contact metamorphic zones, and as a secondary mineral in enriched zones of copper mines.
Uses & applications
A major ore of copper; used for industrial copper extraction and as a popular mineral specimen for collectors due to its colorful tarnish.
Geological facts
Commonly known as 'Peacock Ore' because of its brilliant iridescent tarnish. While naturally occurring, some specimens sold as Peacock Ore are actually Chalcopyrite that has been acid-etched to enhance the colors.
Field identification & locations
Identify by its 'bornite tarnish' (purple/blue shine) and its streak, which is grayish-black. Commonly found in Butte, Montana, and Cornwall, England.
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Mineral
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Mineral/Rock
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