mineral

Pyrite-bearing rock (likely pyrite in quartz or altered host rock)

Pyrite, FeS₂, intergrown with quartz and/or iron-rich matrix

AI-generated identification · may be incorrect

Brassy yellow metallic patches, irregular botryoidal or massive texture, and dark weathered areas are visible; pyrite has Mohs hardness 6–6.5, metallic luster, cubic crystal structure, and no cleavage. The specimen appears rounded and naturally worn, possibly a river cobble or polished rough piece.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Pyrite forms in low-oxygen sedimentary environments, hydrothermal veins, and metamorphic rocks through sulfide mineralization. Its age depends on the host deposit, ranging from ancient Precambrian rocks to young hydrothermal formations.

Uses & applications

Collected as a mineral specimen and used historically as a sulfur source; fine crystals may be decorative, but pyrite is generally unsuitable for jewelry because it tarnishes and can oxidize. Value is usually modest unless crystals, locality, or aesthetics are exceptional.

Geological facts

Pyrite is often called “fool’s gold,” but its harder, sharper brassy appearance and dark streak distinguish it from gold. Oxidation can produce sulfuric acid and iron sulfates, sometimes causing specimen decay.

Field identification & locations

Common in sedimentary basins, ore veins, and metamorphic terrains worldwide, especially Spain, Peru, Italy, China, and the United States. A streak test, hardness test, and close inspection for cubic crystal faces can confirm pyrite; image-only identification is provisional.