mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

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

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

Identified July 20, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in diverse environments including hydrothermal veins, sedimentary deposits under reducing conditions, and as an accessory mineral in igneous rocks. Found in geological formations ranging from Precambrian to recent.

Uses & applications

Historically used to create sparks for firearms (wheel-locks) and as a source of sulfur or sulfuric acid. Today, it is primarily used for jewelry (marcasite jewelry), crystal healing, and mineral collecting.

Geological facts

Nicknamed 'Fool's Gold' because its color and high specific gravity deceived novice prospectors during the gold rushes. Unlike real gold, it is brittle and will shatter if struck rather than flatten.

Field identification & locations

Identify by its brassy color, greenish-black streak (real gold has a yellow streak), and cubic or pyritohedral crystal shapes. Found worldwide, notably in Spain (Rio Tinto), Italy, and the USA.