mineral

Pyrite (“fool’s gold”)

Pyrite, iron disulfide (FeS₂)

AI-generated identification · may be incorrect

Brassy silver-gold metallic luster with granular, partly cubic crystals; Mohs hardness 6–6.5, specific gravity about 5.0, and poor-to-indistinct cleavage. The specimen appears heavily sparkly and may be a natural pyrite cluster or a metallic-coated aggregate.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, sedimentary rocks, coal beds, and metamorphic environments when sulfur-bearing fluids react with iron. Pyrite occurs from Precambrian deposits to modern formations and is widespread worldwide.

Uses & applications

Used historically as a sulfur source and minor iron ore; today it is mainly a collector specimen, though pyrite-bearing ores can be economically important. It is occasionally used decoratively but is not generally suitable for fine jewelry because it tarnishes and can crumble.

Geological facts

Its metallic appearance inspired the name “fool’s gold,” but pyrite is harder and more brittle than gold. Oxidation can produce sulfuric acid and damage stored specimens.

Field identification & locations

Identify by its brassy metallic color, high density, hardness, brittle fracture, and frequent cubic forms; unlike gold, it will not flatten when struck. Common localities include Peru, Spain, Italy, China, the United States, and Canada.