mineral

Pyrite-bearing quartz specimen

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

AI-generated identification · may be incorrect

Metallic brassy-gold, sparkly granular coating on a pale gray-white matrix; pyrite hardness 6–6.5, cubic crystal system, uneven fracture, and specific gravity about 5.0. Quartz is glassy, hardness 7, with no cleavage. The irregular triangular shape appears naturally broken or weathered.

Identified August 24, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed in hydrothermal veins or sulfide-rich sedimentary/metamorphic settings when iron sulfide crystallized with quartz, generally from Paleozoic to younger deposits. Exact age and locality cannot be determined from the image.

Uses & applications

Collected as a “fool’s gold” specimen; pyrite is an industrial sulfur and sulfuric-acid source, while quartz is used in glass, ceramics, abrasives, and electronics. It is usually not suitable for jewelry because pyrite tarnishes and can oxidize.

Geological facts

Pyrite’s brassy color and metallic luster resemble gold, but it is harder and more brittle. A streak test produces a dark greenish-black to brown-black streak, unlike gold’s yellow streak.

Field identification & locations

Common in Peru, Spain, Italy, China, Russia, and the United States. Look for brassy metallic grains, cubic forms, high density, and brittle fracture; avoid prolonged moisture exposure.