mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

AI-generated identification · may be incorrect

Hardness: 6-6.5 Mohs. Color: Pale brass-yellow. Luster: Metallic. Crystal structure: Isometric. Cleavage: Indistinct. Specific gravity: 4.9-5.2.

Hardness: 6-6
Color: Pale brass-yellow
Luster: Metallic

Identified May 6, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs. Color: Pale brass-yellow. Luster: Metallic. Crystal structure: Isometric. Cleavage: Indistinct. Specific gravity: 4.9-5.2.

Formation & geological history

Formed in high and low-temperature hydrothermal veins, by magmatic segregation, and as an accessory mineral in igneous rocks, as well as in sedimentary rocks like shale and coal.

Uses & applications

Previously a source of sulfur and sulfuric acid. Today used in some lithium batteries, jewelry (marcasite jewelry), and as a collector's specimen.

Geological facts

Known as Fool's Gold because it was often mistaken for real gold by prospectors. Unlike gold, it is brittle and will shatter if struck, and it produces a black/greenish streak rather than a gold one.

Field identification & locations

Identify by its cubic crystal habit, brassy color, and hardness (it can scratch glass). Found globally, with notable deposits in Spain, Italy, and the USA.