mineral

Pyrite (iron pyrite)

Pyrite, FeS₂; cubic iron sulfide

AI-generated identification · may be incorrect

Brassy metallic luster with reflective, angular crystal faces; hardness 6–6.5 Mohs, specific gravity about 5.0, and brittle with no prominent cleavage. The specimen appears to be a natural cluster, though individual crystal forms are not clear enough to confirm from the image.

Identified October 13, 2026More mineral →

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Physical properties

Formation & geological history

Forms when iron and sulfur react in a range of settings, including hydrothermal veins and sedimentary rocks; specimens may be millions to billions of years old. Commonly occurs with quartz, sulfides, and coal-bearing strata.

Uses & applications

Used historically as a source of sulfur and, less commonly, iron; today it is collected and used decoratively. It is not suitable as a durable jewelry stone because it is brittle and can oxidize.

Geological facts

Pyrite is nicknamed “fool’s gold” for its metallic color, but it is harder and more brittle than gold and can form cubic crystals.

Field identification & locations

Look for a brassy color, metallic sheen, and brittle breakage; a streak test gives a greenish-black to brownish-black powder. Occurs worldwide, including Spain, Peru, China, and the United States.