mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

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

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

Identified March 18, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in a variety of geological settings including hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and as a result of organic decomposition in sedimentary environments (reducing conditions).

Uses & applications

Major historical source of sulfur and sulfuric acid. Today, it is primarily used in the production of iron sulfate (for water treatment), lithium batteries, and as a popular collector's specimen and ornamental stone.

Geological facts

Famous for its nickname 'Fool's Gold' because its color and weight frequently confused prospectors during the gold rushes. Unlike gold, pyrite is brittle and leaves a greenish-black streak when rubbed against a touchstone.

Field identification & locations

Identify by its cubic crystal habit and brassy metallic sheen; it is harder than a copper penny but can be scratched by a steel blade. Commonly found worldwide, with major deposits in Spain (Rio Tinto), Italy, and the USA (Arizona, Colorado). Collectors look for well-defined 'striations' (fine lines) on crystal faces.