mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

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

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

Identified March 12, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in high and low temperature hydrothermal veins, as an accessory mineral in igneous rocks, and in sedimentary rocks like shale and limestone through precipitation from iron-rich fluids in the presence of sulfur.

Uses & applications

Primarily used in the production of sulfur dioxide for the paper industry and sulfuric acid for chemical manufacturing. Occasionally used as a minor gemstone or ornamental stone and in the manufacturing of lithium-ion batteries.

Geological facts

Its name comes from the Greek word 'pyr' meaning fire, because it emits sparks when struck with steel. It is often found associated with gold, leading to its nickname 'Fool's Gold', though gold is much softer and has a yellow streak whereas pyrite has a greenish-black streak.

Field identification & locations

Identify in the field by its brassy color, cubic crystal habits, and high density. Commonly found globally, notably in Rio Tinto (Spain) and various locations in the USA. Collectors look for sharp, mirror-like cubic or pyritohedron faces.