mineral

Pyrite (likely massive pyrite specimen)

Iron disulfide, FeS₂; cubic/isometric sulfide mineral

AI-generated identification · may be incorrect

Brassy yellow metallic luster with granular to locally crystalline texture; Mohs hardness 6–6.5, specific gravity about 5.0, and no prominent cleavage. The irregular compact form and glittering brass-colored grains are typical of pyrite, though a photo cannot exclude chalcopyrite.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins and sedimentary rocks, especially limestone, shale, and coal; crystals and replacement masses range from ancient to modern geological ages. It commonly precipitates when sulfur-rich fluids react with iron-bearing minerals.

Uses & applications

Used historically as a sulfur source and occasionally for sulfuric-acid production; attractive specimens are collected, but it is rarely used as a gemstone because it tarnishes and can crumble.

Geological facts

Called “fool’s gold,” pyrite is harder and more brittle than gold and usually has a paler, brassy color. Oxidation can produce acidic drainage and iron sulfate minerals.

Field identification & locations

Identify by metallic brass color, high density, brittleness, and dark greenish-black streak; gold leaves a yellow streak and is malleable. Common localities include Peru, Spain, Italy, China, and the United States.