mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6-6.5 (Mohs scale), Color: Brass-yellow, Luster: Metallic, Crystal Structure: Isometric (cubic/pyritohedron crystals), Cleavage: Indistinct/Poor, Specific Gravity: 4.95-5.10

Hardness: 6-6

Identified April 10, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs scale), Color: Brass-yellow, Luster: Metallic, Crystal Structure: Isometric (cubic/pyritohedron crystals), Cleavage: Indistinct/Poor, Specific Gravity: 4.95-5.10

Formation & geological history

Formed in high and low-temperature hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks like shale and coal. Age can range from Billions of years (Precambrian) to recent formations.

Uses & applications

Used as an ore of sulfur and for the production of sulfuric acid. Occasionally used as a gemstone (ornamental), in vintage jewelry (often incorrectly called 'marcasite'), and for lithium-ion batteries.

Geological facts

Commonly known as 'Fool's gold' because its visual appearance misled many gold prospectors throughout history. Despite its yellow color, when rubbed on a streak plate, it leaves a greenish-black streak, unlike gold which leaves a yellow streak.

Field identification & locations

Identify by its brassy color, cubic crystal shape, and high hardness (it can scratch glass). It emits a sulfur smell (rotten eggs) when struck with a hammer. Common worldwide, but notable deposits are in Spain, Italy, and the USA.