mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6.0-6.5 on the Mohs scale; Color: Brass-yellow to pale metallic gold; Luster: Metallic; Crystal system: Isometric/Cubic; Cleavage: Poor/Indistinct; Specific gravity: 4.95-5.10; Streak: Greenish-black to brownish-black

Hardness: 6
Color: Brass-yellow to pale metallic gold
Luster: Metallic

Identified July 26, 2026More mineral →

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Physical properties

Formation & geological history

Forms in a wide variety of geological settings including hydrothermal veins, sedimentary rocks, metamorphic environments, and as an accessory mineral in igneous rocks. Often precipitates from sulfur-rich hydrothermal fluids.

Uses & applications

Historically used as a source of sulfur and sulfuric acid, and in early radio detectors. Currently used primarily as a popular mineral specimen, decorative stone, and occasionally in jewelry (often marketed as marcasite).

Geological facts

Nicknamed 'Fool's Gold' due to its superficial resemblance to real gold. Unlike real gold, pyrite is brittle, much harder, leaves a dark streak instead of a yellow one, and forms sharp geometric cubic or pyritohedral crystals with striations.

Field identification & locations

Identified in the field by its metallic luster, brass-yellow hue, cubic crystal habit with striations on face planes, high density, and hard, brittle nature. Famous locations include Navajún in La Rioja, Spain, as well as Peru, Italy, and the USA.