mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5; Color: Brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Indistinct; Specific Gravity: 4.9-5.2

Hardness: 6-6
Color: Brass-yellow
Luster: Metallic

Identified June 23, 2026More mineral →

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Physical properties

Hardness: 6-6.5; Color: Brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Indistinct; Specific Gravity: 4.9-5.2

Formation & geological history

Forms in hydrothermal veins, as an accessory mineral in igneous rocks, by contact metamorphism, and in sedimentary rocks like shale and coal. Found globally in environments ranging from Precambrian to modern formations.

Uses & applications

Used as an ore for sulfur and sulfuric acid; historically used to start fires (flint); used in jewelry (as marcasite) and as a popular collector's mineral.

Geological facts

Commonly known as Fool's Gold due to its resemblance to precious metals. During WWII, it was mined for sulfur when other sources were cut off. It can sometimes contain trace amounts of actual gold.

Field identification & locations

Identify by its brassy color, cubic crystal habit, and blackish-green streak on a porcelain plate. Common in mines and mountainous regions like the Andes, Alps, and Pyrenees.