mineral

Pyrite

Iron Sulfide (FeS2)

AI-generated identification · may be incorrect

Hardness: 6-6.5 Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubic/orthorhombic); Cleavage: Indistinct; Specific Gravity: 4.8–5.0

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

Identified March 25, 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/orthorhombic); Cleavage: Indistinct; Specific Gravity: 4.8–5.0

Formation & geological history

Forms in hydrothermal veins, as an accessory mineral in igneous rocks, by contact metamorphism, and in sedimentary rocks such as shale and coal. It can be found in rocks from all geological ages.

Uses & applications

Used in the production of sulfur dioxide (for sulfuric acid), as a semiconductor in early radio receivers, and occasionally in jewelry (often sold as 'marcasite'). Collectors value it for its geometric crystal habits.

Geological facts

Commonly known as 'Fool's Gold' due to its resemblance to real gold. Unlike gold, it is brittle and will blacken your skin if you rub it with a streak plate, producing a greenish-black powder. Historically used to create sparks for early firearms (wheellocks).

Field identification & locations

Identify in the field by its brassy color, cubic crystal habits, and high hardness (it can scratch glass, whereas gold cannot). Found worldwide, with famous deposits in Spain, Peru, Italy, and the USA. It often occurs near quartz veins.