mineral

Gold-bearing pyrite-rich rock (iron pyrite)

Pyrite, FeS₂, likely in a quartz- or sulfide-rich matrix

AI-generated identification · may be incorrect

Brassy yellow metallic luster with granular, flaky to massive texture; pyrite hardness 6–6.5 Mohs, cubic crystal structure, poor cleavage, and specific gravity about 5.0. The irregular dark matrix may include quartz, shale, or other sulfides; appearance alone cannot confirm native gold.

Identified September 6, 2026More mineral →

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Physical properties

Formation & geological history

Typically forms hydrothermally in veins and replacement deposits, or diagenetically in sedimentary rocks, from geologically ancient systems ranging from Precambrian to Cenozoic. Gold may occur microscopically within pyrite, but visible gold is not established here.

Uses & applications

Pyrite is mined for sulfur, sulfuric-acid production, and sometimes gold recovery; attractive specimens are collected. It has little jewelry value because it tarnishes and can oxidize.

Geological facts

Often called “fool’s gold”; unlike gold, it is brittle, may form sharp cubes, and leaves a dark greenish-black streak rather than a yellow streak.

Field identification & locations

Look for cubic crystals, brittle fracture, and a dark streak; gold is softer, malleable, and leaves a yellow streak. Common in hydrothermal ore districts worldwide, including Spain, Peru, China, and the United States.