mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow; Luster: Metallic; Crystal Structure: Isometric (cubic, octohedral); Cleavage: Indistinct; Specific Gravity: 4.8-5.0

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

Identified May 21, 2026More mineral →

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Physical properties

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow; Luster: Metallic; Crystal Structure: Isometric (cubic, octohedral); Cleavage: Indistinct; Specific Gravity: 4.8-5.0

Formation & geological history

Formed in hydrothermal veins, by magmatic segregation, or as an authigenic mineral in sedimentary rocks through the reaction of iron and sulfur in anaerobic conditions. Can be found in rocks of all geological ages.

Uses & applications

Historically a source of sulfur for sulfuric acid production; used today in lithium batteries, as a semiconductor, and widely as an ornamental stone or collector's specimen.

Geological facts

Often mistaken for gold due to its color and luster, earning it the nickname 'Fool's Gold.' It can spark when struck against steel, which led to its name derived from the Greek word 'pyr' meaning fire.

Field identification & locations

Identify by its high hardness (cannot be scratched by a copper penny or knife) and its dark green to black streak on a porcelain plate. Found globally, with notable deposits in Spain, Peru, and the USA.