mineral

Likely pyrite-bearing rock fragment

Pyrite, FeS₂, possibly in a dark host rock

AI-generated identification · may be incorrect

Brassy metallic flecks or patches occur on a dark gray-black matrix; pyrite has Mohs hardness 6–6.5, cubic crystal structure, no cleavage, metallic luster, and specific gravity about 5.0. The specimen appears tumbled or naturally rounded, but the image is insufficient for a definitive identification.

Identified September 20, 2026More mineral →

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Physical properties

Formation & geological history

Pyrite forms in hydrothermal veins and sedimentary environments, often replacing organic material or occurring in coal and shale; examples range from Precambrian to modern geological formations. The dark matrix may be shale, basalt, or another fine-grained rock.

Uses & applications

Common pyrite is collected as a mineral specimen and historically served as a source of sulfur and iron; it has little jewelry value because it tarnishes and can oxidize. Attractive crystals and unusual forms may be decorative.

Geological facts

Pyrite is called “fool’s gold,” but it is harder, more brittle, and generally less malleable than gold. It may produce a sulfurous odor when struck or freshly fractured.

Field identification & locations

Look for a pale brass color, metallic luster, cubic shapes, and a dark streak; gold leaves a yellow streak and is much softer. Common localities include Spain, Peru, China, Italy, and the United States.