mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (often cubic, pyritohedral, or octahedral); Cleavage: Indistinct; Specific Gravity: 4.9-5.2

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

Identified June 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins, as an accessory mineral in igneous rocks, by contact metamorphism, and in sedimentary rocks like shale and coal. It forms in oxygen-deficient environments.

Uses & applications

Primarily used as an ore for sulfur and sulfuric acid. It is popular as a collector's specimen and used in costume jewelry (marcasite jewelry). Historically used to create sparks for early firearms.

Geological facts

Commonly known as 'Fool's Gold' because its color and high specific gravity lead many to mistake it for gold. Unlike real gold, it is brittle and will shatter if struck rather than flatten.

Field identification & locations

Identify by its brittle nature, greenish-black streak (gold has a yellow streak), and cubic crystal habits. Found worldwide, with notable deposits in Peru, Spain, and the USA.