mineral

Pyrite (on host rock/ore)

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: 4.8–5.0

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

Identified March 11, 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: 4.8–5.0

Formation & geological history

Formed in hydrothermal veins, as an accessory mineral in igneous rocks, and in sedimentary rocks through biological or chemical precipitation. Found in various geological ages ranging from Precambrian to Holocene.

Uses & applications

Used historically as a source of sulfur and sulfuric acid. Today, it is popular as a collector's specimen and is sometimes used in jewelry (marcasite jewelry). It is also an important ore for tracking gold deposits.

Geological facts

Commonly known as "Fool's Gold" due to its visual similarity to precious metal. Unlike gold, it is brittle and will shatter rather than flatten when struck. It can produce sparks when struck against steel.

Field identification & locations

Identify in the field by its distinct cubic crystal habit, brassy color, and greenish-black streak when rubbed on a porcelain plate. Commonly found globally, particularly in Spain, Peru, and the USA. Collectors look for sharp, lustrous crystal faces.