mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

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

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

Identified March 7, 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; Cleavage: Indistinct; Specific Gravity: 4.9-5.2

Formation & geological history

Forms in a wide variety of geological settings including hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and as authigenic crystals in sedimentary rocks like shale and coal. It can be found in rocks from nearly every geological age.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the production of lithium batteries, as a semiconductor material, and widely collected as mineral specimens. It is occasionally used in jewelry, though its sulfur content makes it prone to tarnishing.

Geological facts

Known as 'Fool's Gold' because its color and metallic luster often deceive novice prospectors. Unlike real gold, pyrite is brittle and will shatter if struck, and it leaves a greenish-black streak when rubbed on a porcelain plate, whereas real gold leaves a yellow streak.

Field identification & locations

Identify in the field by its brassy color, cubic crystal habit, and high density. It is commonly found in Spain, Peru, Italy, and various locations across the United States including Arizona and Colorado. Collectors should look for sharp cubic or pyritohedron shapes.