mineral

Botryoidal pyrite (likely with quartz or chlorite matrix)

Pyrite, FeS₂; botryoidal aggregate

AI-generated identification · may be incorrect

Brassy gray-gold metallic luster, granular to botryoidal crystal masses, commonly brittle, Mohs hardness 6–6.5, specific gravity about 5.0. The subdued color and rough surface suggest weathered or matrix-rich pyrite rather than gold.

Identified August 22, 2026More mineral →

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Physical properties

Formation & geological history

Forms by hydrothermal or sedimentary processes when iron and sulfur precipitate in cavities, veins, or organic-rich sediments; specimens may range from Paleozoic to modern geological settings. Commonly associated with quartz, calcite, shale, and sulfide minerals.

Uses & applications

Used chiefly as a collector specimen and historically as a sulfuric-acid source; attractive bright crystals are occasionally used decoratively, but pyrite is rarely suitable for jewelry because it tarnishes and can oxidize.

Geological facts

Botryoidal means rounded, grape-like growths produced by repeated mineral deposition. Oxidation can generate acidic products and a yellow-brown iron-oxide coating, so store it dry and avoid prolonged humidity.

Field identification & locations

Look for unusually heavy weight, metallic luster, brassy streak (though streak testing may damage it), and inability to scratch it with a steel knife; gold is softer and malleable. Common worldwide, including Spain, Peru, Italy, China, and the United States.