mineral

Quartz-bearing pyrite–chalcopyrite specimen

Pyrite (FeS₂), likely chalcopyrite (CuFeS₂), with quartz (SiO₂)

AI-generated identification · may be incorrect

Metallic brassy-gold sulfide crystals with gray-white, translucent quartz; pyrite hardness 6–6.5, chalcopyrite 3.5–4, quartz 7 Mohs. Sulfides are opaque with metallic luster; quartz is vitreous and commonly hexagonal in crystals.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Hydrothermal sulfide mineralization formed when hot, metal-rich fluids filled fractures or replaced host rock, typically in veins and volcanic-associated deposits. The specimen’s precise age cannot be determined from the image.

Uses & applications

Collected as a display specimen; pyrite and chalcopyrite are important ores of sulfur, iron, and copper, while quartz is widely used in glass, electronics, and construction.

Geological facts

The brassy metallic minerals may tarnish to iridescent colors; chalcopyrite is often marketed as “peacock ore,” though the pictured surface may be natural or treated. Pyrite is commonly called fool’s gold.

Field identification & locations

Identify by metallic luster, high density, angular sulfide crystals, and quartz intergrowth; chalcopyrite is softer and more yellow than pyrite. Common localities include Peru, Mexico, China, Spain, and the U.S. Southwest.