mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6-6.5 (Mohs), Color: Pale brass-yellow, Luster: Metallic, Crystal Structure: Isometric/Cubic, Cleavage: Indistinct, Specific Gravity: 4.9-5.2

Hardness: 6-6

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs), Color: Pale brass-yellow, Luster: Metallic, Crystal Structure: Isometric/Cubic, Cleavage: Indistinct, Specific Gravity: 4.9-5.2

Formation & geological history

Formed in diverse geological settings through hydrothermal veins, as an accessory mineral in igneous rocks, and by precipitation in sedimentary environments containing organic matter.

Uses & applications

Primary source of sulfur and sulfuric acid. Used historically for ignition in firearms and today in jewelry (as 'marcasite'), mineral collecting, and semiconductor research.

Geological facts

Famously known as 'Fool's Gold' due to its superficial resemblance to real gold. Unlike real gold, it is brittle and will turn to powder if crushed rather than flattening.

Field identification & locations

Identify by its metallic luster and greenish-black streak (real gold has a yellow streak). Commonly found in Spain, Peru, Italy, and the USA. Collectors look for perfect cubic or dodecahedral shapes.