mineral

Pyrite (fool’s gold)

Iron disulfide, FeS₂; cubic pyrite-group sulfide

AI-generated identification · may be incorrect

Brassy yellow to pale gold, metallic luster, commonly granular or cubic crystals; Mohs hardness 6–6.5, specific gravity about 5.0, poor cleavage and conchoidal-to-uneven fracture. The irregular specimen appears consistent with massive/granular pyrite, though the image alone cannot confirm it over marcasite or chalcopyr…

Identified September 18, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins and sedimentary rocks, especially coal beds and black shales, through sulfur- and iron-rich fluids or reducing burial environments. Specimens range from Precambrian to modern geological settings.

Uses & applications

Used historically as a sulfur source and minor iron ore; now mainly collected, displayed, and used in educational specimens and jewelry. It is usually inexpensive unless crystals are exceptionally sharp or aesthetically arranged.

Geological facts

Its metallic color resembles gold, but pyrite is harder and more brittle; a streak test gives a greenish-black to brownish-black streak, unlike gold’s yellow streak.

Field identification & locations

Common worldwide, including Spain, Peru, Italy, China, the United States, and Canada. Confirm with hardness, dark streak, brittleness, and lack of malleability; avoid prolonged moisture because pyrite can oxidize and produce acidic residues.