mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

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

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

Identified June 8, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs. Color: Pale brass-yellow. Luster: Metallic. Crystal Structure: Isometric (often cubic or pyritohedral). 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, and in sedimentary environments under reducing conditions.

Uses & applications

Primary source of sulfur and sulfuric acid; historically used in firearms (wheel-lock); used in jewelry (as marcasite) and as a collector specimen.

Geological facts

It earned the name 'Fool's Gold' because its color and high specific gravity lead amateur prospectors to confuse it with real gold. Unlike gold, it is brittle and will powder when crushed.

Field identification & locations

Identify by its hardness (scratches glass, gold does not), brassy color, and greenish-black streak. Commonly found worldwide in variety of geological settings.