mineral
Pyrite-bearing quartz specimen
Pyrite (FeS₂) with quartz (SiO₂), possibly minor chalcopyrite or iron oxides
AI-generated identification · may be incorrectBrassy yellow, metallic pyrite crystals occur with white to translucent, glassy quartz; pyrite hardness is 6–6.5, quartz 7, with cubic pyrite crystal structure and indistinct cleavage. The metallic luster and granular, drusy texture are visible, though tarnish may darken the surface.
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Physical properties
Brassy yellow, metallic pyrite crystals occur with white to translucent, glassy quartz; pyrite hardness is 6–6.5, quartz 7, with cubic pyrite crystal structure and indistinct cleavage. The metallic luster and granular, drusy texture are visible, though tarnish may darken the surface.
Formation & geological history
Typically forms in hydrothermal veins, sulfide-rich sedimentary rocks, and metamorphic environments when iron and sulfur-bearing fluids precipitate pyrite alongside quartz. Formation age depends on locality and cannot be determined from the image.
Uses & applications
Collected as a mineral specimen; pyrite is used industrially as a sulfur source and historically for sulfuric-acid production, while quartz is used in glass, ceramics, electronics, and abrasives.
Geological facts
Pyrite is called “fool’s gold,” but it is harder, more brittle, and usually less malleable than native gold; its cubic crystals and dark streak help distinguish it.
Field identification & locations
Identify by brassy metallic color, high density, brittle fracture, and blackish-green streak; quartz is confirmed by hardness and glassy appearance. Common localities include Peru, Spain, Italy, China, Mexico, and the United States.
