mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 on Mohs scale. Color: Pale brass-yellow to golden. Luster: Metallic. Crystal Structure: Isometric/Cubic. Cleavage: Indistinct. Specific Gravity: 4.9-5.2.

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

Identified July 4, 2026More mineral →

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Physical properties

Hardness: 6-6.5 on Mohs scale. Color: Pale brass-yellow to golden. Luster: Metallic. Crystal Structure: Isometric/Cubic. Cleavage: Indistinct. Specific Gravity: 4.9-5.2.

Formation & geological history

Forms in a wide variety of geological settings, including hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks such as shale and coal. 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 for industrial production of sulfur dioxide, in jewelry (often called 'marcasite'), as a collector's specimen, and in the production of lithium-iron batteries.

Geological facts

Known widely as 'Fool's Gold' because its color and metallic luster frequently lead novice prospectors to mistake it for gold. Unlike gold, which is soft and malleable, pyrite is brittle and harder than a steel knife. It can spark when struck against steel.

Field identification & locations

Identify in the field by its cubic crystal habit, brassy color, and greenish-black streak (gold has a yellow streak). It is commonly found worldwide, with notable deposits in Spain, Peru, Italy, and the USA. Collectors look for well-defined cubes or 'pyritohedron' shapes.