mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: brassy-yellow to gold-like; Luster: metallic; Crystal system: isometric/cubic; Cleavage: indistinct; Specific gravity: approx. 4.9-5.2.

Hardness: 6-6
Color: brassy-yellow to gold-like
Luster: metallic

Identified March 14, 2026More mineral →

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Physical properties

Hardness: 6-6.5 on Mohs scale; Color: brassy-yellow to gold-like; Luster: metallic; Crystal system: isometric/cubic; Cleavage: indistinct; Specific gravity: approx. 4.9-5.2.

Formation & geological history

Formed in high and low-temperature hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks such as shale and coal. It spans almost all geological ages.

Uses & applications

Historically used as a source of sulfur for making sulfuric acid; used in jewelry as marcasite; often collected for its aesthetic hobby value and as an ore of iron (though rarely used as such compared to hematite).

Geological facts

Commonly nicknamed 'Fool's Gold' because its color looks similar to gold. Unlike gold, it is brittle and will shatter if struck, and it creates sparks when struck against steel.

Field identification & locations

Identify by its brassy color, metallic shine, and cubic crystal shapes. It leaves a greenish-black streak on a porcelain plate. Common worldwide, notoriously found in Spain (Rio Tinto), Italy, and the USA.