Mineral

Pyrite

Iron Disulfide (FeS2)

AI-generated identification · may be incorrect

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

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

Identified March 27, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in a wide variety of environments including igneous, metamorphic, and sedimentary settings. It is often created through hydrothermal activity in veins or as a replacement mineral in sedimentary rocks. It is found in geological formations across all ages.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used for aesthetic jewelry (often marketed as 'marcasite'), mineral collecting, and occasionally as an ore for gold (when it contains microscopic inclusions).

Geological facts

Commonly known as 'Fool\'s Gold' because of its visual similarity to gold. Unlike real gold, it is brittle (it breaks rather than flattens when hit), and it creates sparks when struck against steel, which made it important for early firearms.

Field identification & locations

Identify by its brassy color, cubic habit, and greenish-black streak when scratched against a porcelain plate. It is found worldwide, with major deposits in Spain, Italy, Peru, and the USA. Collectors look for sharp, un-oxidized cubic crystals.