mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6–6.5 Mohs scale; Color: Pale brass-yellow with distinct metallic luster; Crystal structure: Isometric (commonly cubic or pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.9–5.2; Streak: Greenish-black to brownish-black.

Hardness: 6–6
Color: Pale brass-yellow with distinct metallic luster
Streak: Greenish-black to brownish-black

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in high and low-temperature hydrothermal veins, by magmatic segregation, and as an accessory mineral in igneous, metamorphic, and sedimentary rocks. It is found in geological settings ranging from Precambrian age to recent deposits.

Uses & applications

Historically used as a source of sulfur and in the manufacturing of sulfuric acid. In modern times, it is used as a decorative stone in jewelry (often called 'marcasite'), as an ore of iron (rarely), and primarily as a popular specimen for mineral collectors.

Geological facts

Widely known as 'Fool's Gold' due to its resemblance to real gold. Unlike real gold, it is brittle and will shatter rather than flatten when struck. It can create sparks when struck against steel, which made it essential for early firearms like the wheel-lock.

Field identification & locations

Identify in the field by its brassy color, cubic crystal habits, and striations on crystal faces. Common locations include Peru, Spain, Italy, and the USA. Collectors look for well-defined 'striated cubes' and avoid specimens showing 'pyrite rot' (oxidation).