mineral

Pyrite (Fool's Gold)

Iron Disulfide (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 May 7, 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

Formed in diverse geological settings through hydrothermal veins, metamorphic rocks, and sedimentary environments under reducing conditions. It is found in rocks of all ages.

Uses & applications

Historically a source of sulfur and sulfuric acid. Today used in lithium batteries, as a semiconductor material, and widely sold as jewelry (marcasite) and collector specimens.

Geological facts

The nickname 'Fool's Gold' comes from its resemblance to precious gold, though it is much harder and more brittle. It is the most common sulfide mineral on Earth's surface.

Field identification & locations

Identify in the field by its cubic crystal habit, brassy color, and greenish-black streak. Unlike gold, it cannot be scratched by a knife and will shatter rather than flatten.