mineral

Pyrite with quartz

Pyrite (FeS₂) with quartz (SiO₂), possibly minor chalcopyrite

AI-generated identification · may be incorrect

Brassy yellow metallic crystals and granular masses with pale translucent-to-white quartz. Pyrite hardness 6–6.5, cubic crystal system, metallic luster, poor cleavage, specific gravity about 5.0; quartz hardness 7, glassy luster, hexagonal structure, no cleavage, specific gravity 2.65.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Usually forms in hydrothermal veins, sedimentary beds, or metamorphic rocks when sulfur-rich fluids react with iron-bearing minerals; specimens may be millions to hundreds of millions of years old. The image most strongly suggests a sulfide-rich hydrothermal specimen.

Uses & applications

Pyrite is an ore of sulfur and historically a minor iron source; quartz is used in glass, electronics, abrasives, and construction. Attractive specimens are sold for display and mineral collections, but pyrite is generally not used as jewelry because it tarnishes and can oxidize.

Geological facts

The metallic color gives pyrite its nickname “fool’s gold,” but its cubic crystals, brittle fracture, and lack of malleability distinguish it from gold. White quartz commonly grows interlocked with pyrite in mineral veins.

Field identification & locations

Identify it by brassy metallic color, dense feel, brittle grains or cubes, and a dark streak rather than gold’s yellow streak; a steel file generally scratches quartz only with difficulty. Common localities include Peru, Spain, Italy, China, Morocco, and the United States.