mineral
Possible chalcopyrite-bearing sulfide fragment
Likely chalcopyrite (CuFeS₂), possibly with pyrite or bornite
AI-generated identification · may be incorrectSmall metallic, brassy-gold to greenish fragment with granular texture; chalcopyrite has Mohs hardness 3.5–4, metallic luster, tetragonal crystals, uneven fracture, and specific gravity about 4.1–4.3. The image is somewhat blurred, so exact identification is uncertain.
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Physical properties
Small metallic, brassy-gold to greenish fragment with granular texture; chalcopyrite has Mohs hardness 3.5–4, metallic luster, tetragonal crystals, uneven fracture, and specific gravity about 4.1–4.3. The image is somewhat blurred, so exact identification is uncertain.
Formation & geological history
Forms mainly in hydrothermal copper deposits, commonly with pyrite, sphalerite, and galena; most specimens formed during ore-deposit activity from the Precambrian through the Cenozoic.
Uses & applications
Important copper ore; attractive crystalline pieces are collected, though it is rarely used as a gemstone because it tarnishes and is relatively soft. Typical small specimens are worth about $3–$25, with exceptional crystals costing more.
Geological facts
Its iridescent blue-green tarnish is often marketed as “peacock ore,” though this appearance may be natural or artificially treated. A copper-streak test and chemical analysis distinguish it reliably from pyrite.
Field identification & locations
Look for brassy metallic color, softness, high density, and possible iridescent tarnish; chalcopyrite is common in copper-mining regions worldwide, including Peru, Mexico, Canada, and the United States. A metallic streak and lack of cubic crystal form help separate it from pyrite.
