metamorphic

Pyrite-bearing quartzite or sulfide-rich metamorphic rock

Quartz (SiO₂) with abundant pyrite (FeS₂), possibly minor mica or chalcopyrite

AI-generated identification · may be incorrect

Granular, sparkly gray-gold specimen with vitreous quartz and brassy metallic sulfide grains; quartz hardness 7, pyrite 6–6.5, no obvious cleavage, and typical specific gravity about 2.65–5.0 depending on sulfide content. The rounded shape appears naturally weathered or tumbled.

Identified September 17, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed when quartz-rich sediment or vein material was metamorphosed and sulfide minerals crystallized or were preserved; age cannot be determined from the image. Common in hydrothermal veins and metamorphic terrains.

Uses & applications

Primarily a collecting specimen; quartzite is used as aggregate and construction stone, while pyrite is an ore indicator and historically used for sulfur and iron production. It is generally not suitable for fine jewelry because pyrite tarnishes and can oxidize.

Geological facts

The brassy glitter may be pyrite, but image-only identification cannot exclude chalcopyrite or mica. A streak test, hardness test, and close examination of crystal shapes would improve confidence.

Field identification & locations

Look for quartz that scratches glass and metallic grains that are harder than a knife; pyrite commonly leaves a dark greenish-black streak, unlike gold’s yellow streak. Worldwide localities include Peru, Spain, China, the United States, and many ore districts.