mineral

Pyrite-bearing rock (iron pyrite)

Pyrite, FeS₂, likely disseminated or massive in a host rock

AI-generated identification · may be incorrect

Brassy-gold metallic luster with granular, uneven texture; pyrite hardness is 6–6.5 Mohs, cubic crystal system, no prominent cleavage, and specific gravity about 5.0. The specimen appears matrix-rich rather than a clean crystal cluster.

Identified August 12, 2026More mineral →

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Physical properties

Formation & geological history

Forms when iron and sulfur react in low-oxygen hydrothermal, sedimentary, or metamorphic environments; individual grains may range from ancient Precambrian to younger deposits. Exact age and host rock cannot be determined from the image.

Uses & applications

Used historically as a sulfur source and occasionally for sulfuric-acid production; attractive pieces are sold as cabinet specimens, but it is rarely used as a gemstone. It has limited construction value.

Geological facts

Often called “fool’s gold,” pyrite is harder and more brittle than gold and commonly produces a dark streak, unlike gold’s yellow streak. Weathering can generate sulfuric acid and iron-oxide staining.

Field identification & locations

Identify by metallic brass color, angular granular form, high density, and dark greenish-black streak; a steel nail will not easily scratch it, while pyrite can scratch glass. Common worldwide in sedimentary basins, hydrothermal veins, and coal beds.