mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6-6.5 (Mohs scale), Color: Brass-yellow, Luster: Metallic (very reflective), Crystal Structure: Isometric (often cubic or framboidal), Cleavage: Indistinct, Specific Gravity: 4.9–5.2

Hardness: 6-6

Identified May 24, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs scale), Color: Brass-yellow, Luster: Metallic (very reflective), Crystal Structure: Isometric (often cubic or framboidal), Cleavage: Indistinct, Specific Gravity: 4.9–5.2

Formation & geological history

Formed in both igneous and sedimentary environments, often through hydrothermal activity or as an authigenic mineral in organic-rich sedimentary rocks under anaerobic conditions.

Uses & applications

Historical source of sulfur and sulfuric acid. Today, it is used in the manufacture of sulfur dioxide for the paper industry and as a popular collector's mineral and in costume jewelry (marcasite).

Geological facts

Known as 'Fool's Gold' due to its resemblance to precious metals. Unlike gold, it is brittle and will spark when struck against steel, a property that led to its name derived from the Greek word for 'fire'.

Field identification & locations

Identify by its brassy color, hardness (it can scratch glass, while gold cannot), and its greenish-black streak when rubbed on a streak plate. Commonly found globally, particularly in Spain, Peru, and the USA.