mineral

Pyrite (fool’s gold)

Iron disulfide, FeS₂; commonly cubic or pyritohedral crystals

AI-generated identification · may be incorrect

Brassy yellow metallic luster with granular, sparkly crystals; Mohs hardness 6–6.5, brittle, specific gravity about 5.0. The specimen appears massive to crystalline, though its shape may be naturally irregular or partly cut.

Identified September 8, 2026More mineral →

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Physical properties

Formation & geological history

Forms in sulfur-rich hydrothermal veins and sedimentary rocks through chemical precipitation and replacement, commonly from the Paleozoic to younger ages. It occurs worldwide, especially in coal beds, shale, limestone, and metallic ore deposits.

Uses & applications

Historically mined for sulfur and sulfuric acid and as an iron source; now used mainly for mineral collecting, education, and display. Quality crystals have modest decorative value.

Geological facts

Its brassy color resembles gold, but pyrite is harder and more brittle: it powders or fractures rather than flattening under a steel tool. A streak test gives a greenish-black to brownish-black streak, unlike gold’s yellow streak.

Field identification & locations

Common localities include Peru, Spain, Italy, China, Russia, and the United States. Identify it by metallic brass color, high density, dark streak, and frequent cubic or pyritohedral crystal faces; definitive identification may require testing because marcasite and chalcopyrite can look similar.