mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

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

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

Identified April 10, 2026More mineral →

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Physical properties

Formation & geological history

Formed in a variety of geological settings including hydrothermal veins, sedimentary rocks (shales and coals), and as an accessory mineral in igneous and metamorphic rocks. It forms in oxygen-depleted environments where sulfur is present.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the production of lithium batteries, glass, and as a popular specimen for rock collectors and in costume jewelry.

Geological facts

Known as 'Fool\'s Gold' because its color and metallic luster often led prospectors to mistake it for gold. However, pyrite is much harder than gold and much more brittle—it will shatter if struck, whereas gold will flatten.

Field identification & locations

Identify in the field by its cubic crystal form, metallic sheen, and its hardness (it can scratch glass). Unlike gold, it has a greenish-black streak and is not malleable. Found globally, with notable deposits in Peru, Spain, and Italy.