mineral

Metallic sulfide mineral specimen, likely pyrite

Pyrite (iron disulfide, FeS₂), possibly mixed with marcasite or chalcopyrite

AI-generated identification · may be incorrect

Hardness about 6–6.5 Mohs; pale brass-yellow to silvery tarnished metallic luster, opaque, commonly cubic or pyritohedral crystals, with uneven fracture and no prominent cleavage. The strongly reflective surface and blocky fracture fit pyrite, though the image alone cannot confirm composition.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, sedimentary rocks, coal beds, and metamorphic environments when iron-rich fluids react with sulfur; deposits range from ancient Precambrian to modern geological settings. The specimen appears partly broken or cut, exposing fresh metallic material.

Uses & applications

Used historically as a sulfur source and currently in sulfuric-acid manufacture, mineral collecting, and decorative specimens; generally not used as a gemstone. Valuable crystals may be displayed or sold to collectors.

Geological facts

Often called “fool’s gold,” pyrite is denser and harder than gold and commonly leaves a dark greenish-black streak rather than a yellow streak. Marcasite has the same chemistry but is less stable and commonly forms spearhead or radiating aggregates.

Field identification & locations

Identify with a brass color, metallic luster, high hardness, and dark streak; a precise identification requires streak, density, and ideally X-ray diffraction or chemical testing. Common localities include Spain, Peru, Italy, China, the United States, and Canada.