mineral

Pyrite specimen

Pyrite, FeS₂ (iron disulfide)

AI-generated identification · may be incorrect

Brassy yellow to gray metallic luster with abundant cubic or granular crystals; Mohs hardness 6–6.5, brittle, opaque, and specific gravity about 5.0. The specimen appears as intergrown, sparkly pyrite crystals in a dark matrix, possibly with minor quartz or sulfides.

Identified September 13, 2026More mineral →

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Physical properties

Formation & geological history

Pyrite commonly forms in hydrothermal veins and sedimentary environments by sulfur-rich fluids reacting with iron; it occurs from Precambrian to modern geological settings. The exact age and locality cannot be determined from the photograph.

Uses & applications

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

Geological facts

Its metallic gold appearance gives it the nickname “fool’s gold,” though its hardness, brittleness, and crystal habits distinguish it from native gold. Pyrite can oxidize in humid conditions to produce acidic iron-sulfate weathering products.

Field identification & locations

Identify it by its brassy metallic color, heavy feel, black-green streak, and frequent cubic crystal faces; unlike gold, it is brittle and cannot be flattened or scratched easily with a knife. Common localities include Spain, Peru, Italy, China, the United States, and Canada.