mineral

Pyrite

Iron Sulfide (FeS2)

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

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

Identified March 12, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in a variety of geological settings including hydrothermal veins, as an accessory mineral in igneous rocks, by contact metamorphism, and in sedimentary rocks such as shale and coal. It can form in almost any geological age where sulfur and iron are present in a reducing environment.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the manufacture of paper, fertilizers, and some electronics. It is very popular in the lapidary arts for jewelry (often sold as 'marcasite' jewelry) and for mineral collecting.

Geological facts

Commonly known as 'Fool's Gold' due to its resemblance to real gold. Unlike gold, pyrite is brittle and creates sparks when struck against steel. In ancient times, it was used to start fires.

Field identification & locations

Identify in the field by its brassy color, cubic crystal habits, and its greenish-black streak (real gold has a golden streak). Found worldwide with notable deposits in Peru, Spain, Italy, and the USA. Collectors look for well-defined cubic or 'sun' formations.