mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

AI-generated identification · may be incorrect

Hardness: 6-6.5 Mohs. Color: Pale brass-yellow. Luster: Metallic. Crystal structure: Isometric (typically cubic or pyritohedral). Cleavage: Poor/indistinct. Specific gravity: 4.8-5.0.

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

Identified April 10, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs. Color: Pale brass-yellow. Luster: Metallic. Crystal structure: Isometric (typically cubic or pyritohedral). Cleavage: Poor/indistinct. Specific gravity: 4.8-5.0.

Formation & geological history

Formed in high and low-temperature hydrothermal veins, by magmatic segregation, and as an accessory mineral in igneous, metamorphic, and sedimentary rocks (including coal beds and black shales).

Uses & applications

Major ore for sulfuric acid and sulfur. Historically used to create sparks in firearms (wheel-locks). Used as a gemstone/jewelry (often sold as 'marcasite') and as a popular collector's mineral.

Geological facts

Known as 'Fool's Gold' because its color and luster often led amateur prospectors to mistake it for real gold. Pyrite is brittle and will shatter if struck, whereas gold is malleable and will dent.

Field identification & locations

Identify by its hardness (scratches glass, unlike gold), green-black streak on porcelain, and metallic yellow shimmer. Commonly found in mining districts worldwide, such as Spain, Peru, and Italy.