mineral

Pyrite-bearing rock, likely pyrite quartzite or sulfide ore

Pyrite (FeS₂), possibly with quartz and minor iron sulfides

AI-generated identification · may be incorrect

Brassy yellow metallic grains with a granular, massive texture; pyrite hardness is 6–6.5 Mohs, cubic crystal system, no prominent cleavage, and specific gravity about 5.0. The specimen appears weathered and matrix-rich rather than a clear crystal cluster.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Pyrite commonly forms in hydrothermal veins, sedimentary beds, and metamorphic sulfide deposits through sulfur-rich reactions involving iron. Its age depends on the deposit; similar specimens occur from Precambrian to modern geological settings.

Uses & applications

Used historically as a sulfur source and occasionally for sulfuric-acid production; attractive pieces are collected, but it is generally unsuitable for jewelry because it tarnishes and can oxidize to acidic minerals.

Geological facts

Often called “fool’s gold,” pyrite is usually harder and more brittle than gold and tends to form cubic or pyritohedral crystals. A streak test produces a greenish-black to brown-black streak, unlike gold’s yellow streak.

Field identification & locations

Identify by metallic brass color, high density, brittle fracture, and dark streak; avoid prolonged moisture because oxidation can create sulfuric acid. Common localities include Peru, Spain, Italy, China, and the United States.