mineral

Pyrite-bearing quartz (likely chalcopyrite/pyr ite specimen)

Pyrite, FeS₂, with quartz (SiO₂) and possibly chalcopyrite, CuFeS₂

AI-generated identification · may be incorrect

Metallic brassy-gold sulfide crystals in a gray, translucent quartz-rich matrix; pyrite hardness 6–6.5 Mohs, chalcopyrite 3.5–4, with uneven fracture and no prominent cleavage. The granular, glittering texture and tarnished iridescent surfaces are typical of sulfide minerals.

Identified August 24, 2026More mineral →

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Physical properties

Formation & geological history

Hydrothermal veins and sulfide-rich ore deposits formed when hot, mineral-laden fluids cooled in fractures, commonly during Precambrian to Mesozoic geological events. Exact age and identity require hardness, streak, and chemical testing.

Uses & applications

Collected as a mineral specimen; pyrite is historically used for sulfur and sulfuric-acid production, while associated copper sulfides are copper ores. Usually unsuitable for jewelry because sulfides tarnish and can oxidize.

Geological facts

Pyrite is called “fool’s gold,” but it is generally harder, paler, and more angular than native gold; chalcopyrite often shows stronger rainbow tarnish. Acidic oxidation of sulfides can produce sulfuric acid and acid mine drainage.

Field identification & locations

Look for brassy metallic luster, dark greenish-black streak, and crystals or granular masses; pyrite will not scratch easily with a knife, whereas chalcopyrite may. Common localities include Spain, Peru, Mexico, the United States, and China.