mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 Mohs; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubes, pyritohedrons); Cleavage: Indistinct; Specific Gravity: 4.9-5.2

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

Identified April 7, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubes, pyritohedrons); Cleavage: Indistinct; Specific Gravity: 4.9-5.2

Formation & geological history

Forms in a wide variety of geological environments, including hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks like shale and coal. Found globally across all geological eras.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in jewelry (as 'marcasite'), as a collector's specimen, and can sometimes be mined as an indicator/source of subordinate gold.

Geological facts

Commonly known as 'Fool's Gold' because its metallic luster and brassy hue often led novice prospectors to mistake it for real gold. Unlike gold, pyrite is brittle and leaves a greenish-black streak when rubbed on a porcelain plate.

Field identification & locations

Identify by its hardness (cannot be scratched by a penny), its cubic crystal habit, and its distinctive metallic sheen. It is found worldwide, with high-quality cubic specimens famously coming from Navajun, Spain.