mineral
Weathered metallic sulfide fragment, possibly pyrite-bearing rock
Likely iron sulfide (pyrite, FeS₂) in a weathered host rock; exact identification requires testing
AI-generated identification · may be incorrectBrassy yellow-gray color with dull to weak metallic luster, irregular granular texture, and no obvious cleavage; estimated Mohs hardness 6–6.5 if pyrite, though the pictured weathered matrix may be softer. The rounded, oxidized surface suggests alteration rather than a fresh crystal face.
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Physical properties
Brassy yellow-gray color with dull to weak metallic luster, irregular granular texture, and no obvious cleavage; estimated Mohs hardness 6–6.5 if pyrite, though the pictured weathered matrix may be softer. The rounded, oxidized surface suggests alteration rather than a fresh crystal face.
Formation & geological history
Pyrite forms in hydrothermal veins, sedimentary rocks, and metamorphic settings from sulfur- and iron-rich fluids; deposits range from Precambrian to recent. Weathering produces brown, gray, or greenish oxidation coatings and may remove the original brassy luster.
Uses & applications
Common pyrite is used chiefly as a geological indicator and collector specimen; historically it supplied sulfur for sulfuric acid production. It has limited jewelry use because it tarnishes and can crumble when weathered.
Geological facts
Pyrite is commonly called “fool’s gold,” but it is harder, more brittle, and typically less malleable than native gold. A streak test, hardness test, and specific-gravity measurement are needed to distinguish it from chalcopyrite, marcasite, or gold.
Field identification & locations
Look for brassy metallic color, cubic crystal forms, dark greenish-black streak, and inability to be cut or flattened like gold; avoid powdering unknown sulfides. Common occurrences include sedimentary beds, quartz veins, and ore districts worldwide.
