mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

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

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

Identified March 28, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in a variety of geological environments including sedimentary deposits (precipitated by bacteria in anoxic conditions), hydrothermal veins, and metamorphic rocks. It has been forming since the early Precambrian period.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the manufacture of lithium batteries, as a semiconductor material, and widely sold as jewelry and collector specimens.

Geological facts

Its name comes from the Greek word 'pyr' meaning fire, because it produces sparks when struck against steel. It is famously known as 'Fool\'s Gold' because its color and luster led many prospectors to mistake it for real gold.

Field identification & locations

Identify in the field by its brittleness (gold is malleable), metallic luster, and black/greenish-black streak when rubbed on ceramic. Common locations include Peru, Spain (Rio Tinto), Italy, and the USA (Arizona/Colorado).