mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

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

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

Identified June 2, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in high and low-temperature hydrothermal veins, as an accessory mineral in igneous rocks, and in sedimentary rocks through metamorphic or diagenetic processes. Found in all geologic ages.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used for manufacturing lithium-ion batteries, as a semiconducting material, and extensively in jewelry (as marcasite) and as a collector's mineral.

Geological facts

Often mistaken for gold, hence the name 'Fool's Gold'. It can create sparks when struck against steel. Notable for frequently forming near-perfect natural cubes.

Field identification & locations

Identify in the field by its brittle nature and greenish-black streak (real gold is malleable and has a golden streak). Commonly found in Spain, Italy, Peru, and the USA. Look for the characteristic brassy luster.