mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (often cubic, octahedral, or pyritohedral); Cleavage: Indistinct; Specific Gravity: Approx. 4.9-5.2; Streak: Greenish-black to brownish-black

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

Identified March 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed in various geological environments including hydrothermal veins, by segregation from magmas, as an accessory mineral in igneous rocks, and in sedimentary rocks through metamorphic or biochemical processes. It can be found in rocks spanning all geological ages.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the manufacture of lithium batteries, glass, and as a popular specimen for mineral collectors. Some jewelry uses it under the name "marcasite."

Geological facts

Commonly known as "Fool's Gold" due to its visual similarity to precious metal. Unlike gold, it is brittle and will spark when struck against steel, which led to its use in wheel-lock firearms in the 16th century.

Field identification & locations

Identify in the field by its brassy color, hardness (it can scratch glass), and cubic crystal habit. It is found worldwide, with notable deposits in Spain (Rio Tinto), Peru, and the USA. Collectors should look for sharp crystal faces and a high metallic sheen.