mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6–6.5 Mohs scale; Color: Pale brass-yellow, tarnishing darker; Luster: Metallic; Crystal Structure: Isometric (often cubic or pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.8–5.0

Hardness: 6–6
Color: Pale brass-yellow, tarnishing darker
Luster: Metallic

Identified March 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms in diverse geological environments including hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks like shale and coal. It can form at any geological age.

Uses & applications

Historically used as a source of sulfur for sulfuric acid production; currently used in jewelry (as marcasite), in lithium batteries as cathode material, and as a popular collector's specimen.

Geological facts

Known as 'Fool's Gold' because its color and high specific gravity lead novice prospectors to mistake it for gold. It is also sparks when struck against steel, leading to its name derived from the Greek word 'pyr' meaning fire.

Field identification & locations

Identify by its brittle nature, greenish-black streak (gold has a yellow streak), and cubic crystal habit. Commonly found in Spain (Rio Tinto), Peru, Italy, and the USA. Collectors look for well-defined cubic or dodecahedral faces.