mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6.0-6.5 Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubes, pyritohedrons, octahedrons); Cleavage: Indistinct; Specific Gravity: 4.8-5.0

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

Identified February 21, 2026More mineral →

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Physical properties

Hardness: 6.0-6.5 Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubes, pyritohedrons, octahedrons); Cleavage: Indistinct; Specific Gravity: 4.8-5.0

Formation & geological history

Forms in diverse environments including hydrothermal veins, sedimentary rocks (via sulfate-reducing bacteria), and metamorphic contact zones. It is the most common sulfide mineral and can be found in rocks of all geological ages.

Uses & applications

Primarily used as an ore of sulfur for sulfuric acid production; also used in costume jewelry (often sold as 'marcasite'), mineral collecting, and historically as a source of sparks in firearms.

Geological facts

Commonly known as 'Fool's Gold' because its color mislead early prospectors into thinking they had found gold. It is unique among minerals for frequently forming near-perfect natural cubes and having striations on its crystal faces.

Field identification & locations

Identify in the field by its metallic luster, golden color, and its greenish-black streak (real gold has a yellow streak). It is brittle and will shatter if struck, unlike gold which is malleable. Highly common in Spain (Navajún), Peru, and Italy.