mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 (Mohs scale), Color: Brass-yellow, Luster: Metallic, Crystal structure: Isometric (cubes, pyritohedrons), Cleavage: Indistinct, Specific Gravity: 4.9-5.2

Hardness: 6-6

Identified July 9, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs scale), Color: Brass-yellow, Luster: Metallic, Crystal structure: Isometric (cubes, pyritohedrons), Cleavage: Indistinct, Specific Gravity: 4.9-5.2

Formation & geological history

Formed in high and low-temperature hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks such as shale and coal. Found across all geological ages.

Uses & applications

Major source of sulfur for sulfuric acid production; historically used for firearms (wheel-lock); used in jewelry as 'marcasite'; popular for mineral collectors.

Geological facts

Commonly known as 'Fool's Gold' due to its resemblance to real gold. It can generate sparks when struck against steel, which made it vital for early fire-starting and firearms technology.

Field identification & locations

Identify by its brittle nature (gold is malleable) and its greenish-black streak (gold has a yellow streak). Found globally, with notable deposits in Spain, Italy, and the USA. Collectors look for well-defined cubic crystals.