mineral

Pyrite-bearing sulfide specimen

Pyrite (FeS₂), possibly with chalcopyrite (CuFeS₂) and/or marcasite

AI-generated identification · may be incorrect

Brassy metallic-gold crystals and granular gray-gold sulfides; pyrite hardness 6–6.5 Mohs, metallic luster, cubic crystal system, poor cleavage, and specific gravity about 5.0. The irregular mass and mixed colors prevent confident species identification from the image alone.

Identified September 21, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, sedimentary rocks, and metamorphic environments through sulfur-rich mineralizing fluids; specimens may range from ancient to recently exposed deposits. Associated sulfides commonly crystallize together in ore bodies.

Uses & applications

Collected as a mineral specimen and used historically as an iron-sulfur ore; chalcopyrite-bearing material may be copper ore. Attractive crystals are sometimes used decoratively, but it is generally not a gemstone.

Geological facts

Pyrite is commonly called “fool’s gold,” but its greater hardness, darker streak, and often cubic crystals distinguish it from native gold. Oxidation can produce sulfuric acid and rusty iron sulfates.

Field identification & locations

Look for a pale brassy color, metallic luster, cubic or granular texture, and a dark greenish-black streak; gold is much softer and leaves a yellow streak. Common sources include Spain, Peru, Italy, China, and the United States.