mineral

Pyrite

Iron Sulfide (FeS2)

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

Hardness: 6-6

Identified July 21, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in a wide variety of geological settings including hydrothermal veins, as an accessory mineral in igneous rocks, and in sedimentary environments (reducing conditions) over millions of years.

Uses & applications

Historically used for making sulfuric acid and ignition in firearms; currently used in jewelry (as marcasite), industrial sulfur production, and as a popular collector specimen.

Geological facts

Commonly known as Fool's Gold due to its resemblance to real gold; unlike gold, it is brittle and will powder if crushed rather than flattening. It can produce sparks when struck against steel.

Field identification & locations

Identify by its brassy color, greenish-black streak, and cubic or pyritohedral crystal habits. Found globally in major deposits in Spain, Italy, Peru, and the USA. Collectors value well-formed crystal clusters.