mineral

Pyrite

Iron Disulfide (FeS2)

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

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

Identified June 28, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in high and low-temperature hydrothermal veins, by magmatic segregation, in metamorphic rocks, and as a replacement mineral in sedimentary rocks. Found throughout all geological eras.

Uses & applications

A major ore for sulfuric acid production; historically used in firearms (wheel-locks); used in inexpensive jewelry (as marcasite); significant to collectors and as a decorative stone.

Geological facts

Known as 'Fool's Gold' due to its resemblance to precious gold. Unlike gold, it is brittle and creates sparks when struck against steel. It is actually sometimes found in association with real gold deposits.

Field identification & locations

Identify by its brassy color, metallic luster, greenish-black streak (real gold has a yellow streak), and its brittleness. Commonly found in mining districts in Peru, Spain, Italy, and the USA.