mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Hardness: 6-6.5 Mohs; Color: Brass-yellow or pale gold; Luster: Metallic; Crystal Structure: Isometric (cubic or pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.8-5.0

Hardness: 6-6
Color: Brass-yellow or pale gold
Luster: Metallic

Identified July 13, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs; Color: Brass-yellow or pale gold; Luster: Metallic; Crystal Structure: Isometric (cubic or pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.8-5.0

Formation & geological history

Formed in a variety of geological environments including sedimentary deposits (often as nodules), hydrothermal veins, and as an accessory mineral in igneous and metamorphic rocks. It forms through the reaction of sulfur and iron in oxygen-poor environments.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the manufacture of solar panels, lithium batteries, and as a popular collector's specimen. Occasionally used in jewelry under the name 'marcasite'.

Geological facts

Pyrite is nicknamed 'Fool's Gold' because its color and weight can lead novice miners to mistake it for real gold. However, pyrite is much harder than gold and brittle, whereas gold is soft and malleable.

Field identification & locations

Identified in the field by its distinct metallic brassy luster and cubic crystal habits. Unlike gold, pyrite will create a greenish-black streak when rubbed against a porcelain plate and can produce sparks when struck against steel.