mineral
Likely gold-bearing sulfide mineral, possibly chalcopyrite
Chalcopyrite (CuFeS₂), tentative identification
AI-generated identification · may be incorrectBrassy yellow to bronze, metallic luster, irregular granular surface; Mohs hardness 3.5–4, tetragonal crystal system, poor cleavage, specific gravity about 4.1–4.3. The image alone cannot confirm whether the bright material is native gold or another sulfide.
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Physical properties
Brassy yellow to bronze, metallic luster, irregular granular surface; Mohs hardness 3.5–4, tetragonal crystal system, poor cleavage, specific gravity about 4.1–4.3. The image alone cannot confirm whether the bright material is native gold or another sulfide.
Formation & geological history
Typically forms in hydrothermal copper deposits, commonly with pyrite, sphalerite, and quartz during magmatic-hydrothermal activity; age varies widely by deposit. Native gold, if present, may occur as inclusions or coatings.
Uses & applications
Major copper ore and a collector mineral; attractive specimens are displayed, but ordinary pieces have modest value. Gold-bearing material may have assay value.
Geological facts
Chalcopyrite often develops iridescent blue-purple tarnish (“peacock ore”), though this specimen appears naturally brassy rather than strongly iridescent.
Field identification & locations
Check for a green-black streak and brittleness: chalcopyrite powder is dark green-black and the mineral crumbles, while native gold leaves a yellow streak and deforms rather than shattering. Common worldwide, including Chile, Peru, Canada, Australia, and the United States.
