mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

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 July 9, 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 diverse geological settings, including hydrothermal veins, sedimentary rocks through biological reduction of sulfates, and as an accessory mineral in igneous rocks.

Uses & applications

Historically a source of sulfur and sulfuric acid. Today, it is used in the manufacture of lithium batteries, as a mineral specimen for collectors, and occasionally in jewelry (often incorrectly called marcasite).

Geological facts

It is nicknamed Fool's Gold due to its visual similarity to gold, though it is much harder and more brittle. It can create sparks when struck against steel.

Field identification & locations

Identify by its brassy color, metallic luster, and blackish-green streak on a porcelain plate. It is found globally, with notable deposits in Spain, Italy, and Peru.