mineral

Pyrite

Iron Disulfide (FeS2)

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

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

Identified July 6, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in a wide variety of geological settings including hydrothermal veins, by segregation from magmas, as an accessory mineral in igneous rocks, and in sedimentary rocks where it can form through the action of bacteria under anaerobic conditions.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today it is used in the manufacture of lithium batteries, solar panels, and as a popular specimen for educational purposes and jewelry (often called 'marcasite' in trade).

Geological facts

Known as 'Fool's Gold' because of its visual similarity to precious gold. Unlike gold, pyrite is brittle and leaves a greenish-black streak on a streak plate. It can spark when struck against steel.

Field identification & locations

Identify in the field by its metallic luster, golden hue, and cubic crystal habits. Look for it in quartz veins or sedimentary shale. It is found globally, with major deposits in Spain, Peru, and the USA.