mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubic/octahedral/pyritohedron); Cleavage: Indistinct; Specific Gravity: Approx. 5.0

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

Identified June 17, 2026More mineral →

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Physical properties

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubic/octahedral/pyritohedron); Cleavage: Indistinct; Specific Gravity: Approx. 5.0

Formation & geological history

Formed in diverse geological settings including hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary environments (shales and coals) through the action of bacteria in low-oxygen conditions.

Uses & applications

Historically a source of sulfur and sulfuric acid. Today used in some lithium batteries, as a semiconductor material, and widely for jewelry (known as marcasite) and as common collector specimens.

Geological facts

Often called 'Fool's Gold' because of its resemblance to actual gold, though it is much harder and more brittle. It can produce sparks when struck against steel or flint, a property used by early humans to start fires.

Field identification & locations

Identify in the field by its brassy color, cubic crystal habits, and black/green-black streak. It is common worldwide, frequently associated with quartz veins or found within sedimentary nodules.