mineral
Metallic sulfide mineral specimen, likely pyrite
Pyrite (FeS₂), possibly mixed with marcasite or another iron sulfide
AI-generated identification · may be incorrectSmall rounded gray-silver metallic piece with granular/crystalline texture; pyrite has Mohs hardness 6–6.5, cubic crystal structure, metallic luster, and usually brass-yellow color, while marcasite is paler silver-gray. Specific gravity is approximately 4.8–5.0; the photograph alone cannot confirm identity.
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Physical properties
Small rounded gray-silver metallic piece with granular/crystalline texture; pyrite has Mohs hardness 6–6.5, cubic crystal structure, metallic luster, and usually brass-yellow color, while marcasite is paler silver-gray. Specific gravity is approximately 4.8–5.0; the photograph alone cannot confirm identity.
Formation & geological history
Iron sulfides form in reducing, sulfur-rich hydrothermal veins and sedimentary environments through geological processes spanning many ages. The rounded shape suggests it may be tumbled, weathered, or a polished fragment rather than a natural crystal cluster.
Uses & applications
Collected as a mineral specimen and sometimes used historically as a sulfur or iron source; pyrite is not generally used as jewelry because it can tarnish and oxidize. It has limited industrial value today.
Geological facts
Pyrite is called “fool’s gold,” but its pale brass color, higher hardness, and cubic crystals distinguish it from gold. Marcasite can produce acidic oxidation products and should be kept dry.
Field identification & locations
Test hardness against glass, inspect for cubic striated faces, and check streak: pyrite is greenish-black to brown-black, whereas gold leaves a yellow streak. Common localities include Spain, Peru, Italy, China, and the United States.
