mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 Mohs scale; Color: Pale brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Poor/Indistinct; Specific Gravity: 4.8-5.0

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

Identified July 5, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs scale; Color: Pale brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Poor/Indistinct; Specific Gravity: 4.8-5.0

Formation & geological history

Formed in diverse geological environments including hydrothermal veins, contact metamorphism, and as an authigenic mineral in sedimentary rocks under anaerobic conditions. It is found in rocks of all geological ages.

Uses & applications

Historically used to create sparks for firearms; currently used in the production of sulfuric acid, as a semiconductor in solar cells, and frequently sold as ornamental specimens or jewelry known as 'marcasite'.

Geological facts

Nicknamed 'Fool's Gold' because of its visual similarity to precious metal. It is the most common sulfide mineral and can sometimes contain small amounts of actual gold within its structure.

Field identification & locations

Identified in the field by its brassy color, cubic or pyritohedron crystal habits, and a greenish-black streak. Common in mining districts worldwide, such as Peru, Spain, and the USA. Collectors look for sharp, mirror-like crystal faces.