mineral

Pyrite-bearing rock (likely pyrite in a dark host rock)

Pyrite, FeS₂, with an unidentified host matrix

AI-generated identification · may be incorrect

Brassy metallic flecks contrast with a dark, rough matrix. Pyrite has Mohs hardness 6–6.5, cubic crystals, no true cleavage, and specific gravity around 5; the specimen’s matrix cannot be determined from the image.

Identified September 27, 2026More mineral →

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Physical properties

Formation & geological history

Pyrite forms in many settings, including hydrothermal veins and sedimentary rocks, when iron and sulfur combine under oxygen-poor conditions. The specimen’s age and precise formation environment are not identifiable from appearance alone.

Uses & applications

Pyrite is collected as a mineral specimen and has historically been used as a sulfur source; it is not typically used as an ore today. Its metallic appearance is sometimes used decoratively, but it can oxidize and produce acidic drainage.

Geological facts

Pyrite is often called “fool’s gold,” but it is harder and more brittle than gold and commonly forms cubic crystals.

Field identification & locations

Look for a brassy color, metallic luster, and brittle fracture; a streak test yields a dark greenish-black streak. Pyrite occurs worldwide in veins and sedimentary deposits; this small, uncrystallized piece is roughly $2–$15.