mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Hardness: 6-6.5 (Mohs), Color: Brass-yellow, Luster: Metallic, Crystal System: Isometric (often cubic or pyritohedral), Cleavage: Indistinct/Poor, Specific Gravity: 4.9-5.2

Hardness: 6-6

Identified July 18, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs), Color: Brass-yellow, Luster: Metallic, Crystal System: Isometric (often cubic or pyritohedral), Cleavage: Indistinct/Poor, Specific Gravity: 4.9-5.2

Formation & geological history

Formed in hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks like coal and shale through biological or chemical replacement processes.

Uses & applications

Historically used for the production of sulfuric acid and sulfur. It is occasionally used as a gemstone (marcasite jewelry) and is popular among mineral collectors.

Geological facts

Known as Fool's Gold due to its resemblance to real gold. Unlike gold, which is soft and leaves a yellow streak, pyrite is brittle and leaves a greenish-black streak. It can spark when struck against steel.

Field identification & locations

Identified by its brassy color, high hardness (cannot be scratched by a penny), and metallic sheen. Commonly found worldwide in diverse geological environments from quartz veins to coal beds.