mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6–6.5 Mohs. Color: Pale brass-yellow to golden-yellow. Luster: Metallic. Crystal Structure: Isometric (often cubic, pyritohedral, or octahedral). Cleavage: Poor performance/Indistinct. Specific Gravity: 4.9–5.2.

Hardness: 6–6
Color: Pale brass-yellow to golden-yellow
Luster: Metallic

Identified March 18, 2026More mineral →

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Physical properties

Formation & geological history

Forms in diverse environments including magmatic segregation, hydrothermal veins, and sedimentary deposits under anaerobic conditions. It is common throughout Earth's history from the Archean to the present.

Uses & applications

Historically used to create sparks for firearms (wheel-locks) and as a source of sulfur for sulfuric acid. Used today in jewelry (labeled as 'marcasite'), mineral collecting, and solar panels.

Geological facts

Commonly known as 'Fool's Gold' because its color and weight can lead novice prospectors to mistake it for gold. Unlike real gold, it is brittle, leaves a greenish-black streak, and cannot be scratched by a copper penny.

Field identification & locations

Identify by its metallic luster, golden color, and often perfectly cubic crystal habits. Found worldwide, with notable deposits in Spain, Peru, Italy, and the USA. Collectors look for sharp, mirror-like faces and unique crystal clusters.