mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6-6.5; Color: Brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Indistinct; Specific Gravity: 4.9-5.2

Hardness: 6-6
Color: Brass-yellow
Luster: Metallic

Identified July 2, 2026More mineral →

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Physical properties

Hardness: 6-6.5; Color: Brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Indistinct; Specific Gravity: 4.9-5.2

Formation & geological history

Forms in sedimentary rocks as authigenic minerals, in igneous rocks as an accessory mineral, and in metamorphic rocks through hydrothermal activity. It forms across various geological ages.

Uses & applications

Historically used to produce sulfuric acid and sulfur. Today, it is primarily used as a decorative stone, in jewelry (marcasite jewelry), and as a minor ore of gold when associated with auriferous deposits.

Geological facts

Commonly known as 'Fool's Gold' because its color and luster resemble real gold. However, pyrite is much harder and leaves a black or greenish-black streak, whereas gold leaves a yellow streak.

Field identification & locations

Identified by its brassy color, cubic or pyritohedral crystal habit, and high specific gravity. Found globally, with notable deposits in Spain, Italy, and the USA. Collectors check for its brittle nature compared to gold's malleability.