mineral

Pyrite

Iron Sulfide (FeS2)

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

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

Identified May 4, 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, octahedral, pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.8-5.0

Formation & geological history

Forms in a wide variety of geological settings including hydrothermal veins, contact metamorphic deposits, and as an accessory mineral in igneous and sedimentary rocks. It is found in deposits ranging from Precambrian to modern times.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the manufacture of lithium batteries, as a semiconductor material, and widely sold as a decorative mineral or jewelry (often called 'marcasite' in trade).

Geological facts

Commonly known as 'Fool's Gold' because its color and metallic luster often led inexperienced prospectors to mistake it for real gold. It can create sparks when struck against steel, which led to its use in wheel-lock firearms.

Field identification & locations

Identify in the field by its cubic crystal habit, brassy color, and greenish-black streak (unlike gold, which has a golden streak). Frequently found in Spain, Peru, Italy, and the USA. Collectors look for sharp, mirror-like cubic faces.