mineral

Pyrite-bearing rock, possibly pyrite-rich schist or quartzite

Pyrite (iron disulfide, FeS₂) in a fine-grained metamorphic or quartz-rich matrix

AI-generated identification · may be incorrect

Metallic brassy-gold sparkle; pyrite hardness 6–6.5 Mohs, cubic crystal structure, poor cleavage, and specific gravity about 5.0. The rounded, greenish-gray specimen appears matrix-rich rather than a single crystal, with granular glitter and possible foliation.

Identified August 17, 2026More mineral →

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Physical properties

Formation & geological history

Pyrite commonly forms in hydrothermal veins and sedimentary or metamorphic rocks through sulfide mineralization. The host rock may be Paleozoic or younger, but age cannot be determined from the photograph.

Uses & applications

Used historically as a sulfur and sulfuric-acid source; attractive pieces are sold as teaching specimens and mineral collectibles, though it is rarely used in jewelry because it tarnishes and can oxidize.

Geological facts

Often called “fool’s gold,” pyrite is denser and harder than gold and produces a dark streak rather than a yellow one. Weathering may create sulfuric acid and iron-oxide coatings.

Field identification & locations

Look for a brassy metallic luster, dark greenish-black streak, and angular cubic crystals; it should not flatten under a steel knife. Common localities include Spain, Peru, Italy, China, and the United States; this rounded piece may be tumbled or naturally worn.