mineral
Likely bornite (“peacock ore”)
Bornite, Cu₅FeS₄
AI-generated identification · may be incorrectA small, dark metallic specimen with blue-violet iridescence, consistent with tarnished bornite; hardness 3. Mohs, metallic luster, and an orthorhombic crystal structure. The image is too small to confirm its composition.
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Physical properties
A small, dark metallic specimen with blue-violet iridescence, consistent with tarnished bornite; hardness 3. Mohs, metallic luster, and an orthorhombic crystal structure. The image is too small to confirm its composition.
Formation & geological history
A copper-iron sulfide formed in hydrothermal copper deposits and some contact-metamorphic deposits; specimens occur across a wide range of geological ages.
Uses & applications
Bornite is an important copper ore and is also collected for its vivid tarnish; it is not generally used as a gemstone.
Geological facts
Its colorful surface is a thin oxidation tarnish, not the mineral’s fresh color; bornite is often confused with chalcopyrite.
Field identification & locations
Look for a heavy, metallic copper sulfide with blue-purple tarnish, commonly associated with chalcopyrite and other copper ores. Found in copper-mining regions worldwide, including the Americas and Europe.
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