mineral
Peacock ore (iridescent chalcopyrite), likely heat-treated
Chalcopyrite, CuFeS₂; commonly sold as artificially oxidized “peacock ore”
AI-generated identification · may be incorrectMetallic luster with intense blue, purple, and turquoise tarnish; massive, nontransparent crystals and indistinct cleavage. Mohs hardness 3.5–4, specific gravity about 4.1–4.3; brass-yellow fresh surfaces commonly show iridescence after treatment.
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Physical properties
Metallic luster with intense blue, purple, and turquoise tarnish; massive, nontransparent crystals and indistinct cleavage. Mohs hardness 3.5–4, specific gravity about 4.1–4.3; brass-yellow fresh surfaces commonly show iridescence after treatment.
Formation & geological history
Chalcopyrite forms in hydrothermal copper deposits, commonly with pyrite, sphalerite, and quartz, from Precambrian to modern geological settings. The vivid colors generally result from surface oxidation or heat treatment rather than natural crystal color.
Uses & applications
Collected as a decorative mineral and lapidary specimen; chalcopyrite is an important copper ore, though these treated pieces have little industrial value.
Geological facts
The blue-purple coating is a thin interference-oxide film, not the mineral’s intrinsic color. Natural bornite (“true peacock ore”) can look similar but is softer and typically more copper-rich.
Field identification & locations
Identify by metallic brassy areas, relatively low hardness, and blue-purple tarnish; a steel point may scratch it, while copper-colored streak or sulfide odor may appear when abraded. Common localities include Peru, Mexico, Arizona, and Cornwall.
