mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 on Mohs scale. Color: Pale brass-yellow. Luster: Metallic. Crystal structure: Isometric (often cubic or dodecahedral). Cleavage: Poor/Indistinct. Specific gravity: 4.9-5.2.

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

Identified March 18, 2026More mineral →

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Physical properties

Hardness: 6-6.5 on Mohs scale. Color: Pale brass-yellow. Luster: Metallic. Crystal structure: Isometric (often cubic or dodecahedral). Cleavage: Poor/Indistinct. Specific gravity: 4.9-5.2.

Formation & geological history

Forms in a wide variety of geological environments including sedimentary rocks (reduction by bacteria), metamorphic rocks (contact metamorphism), and igneous rocks (magmatic segregation or hydrothermal veins). It can be found in rocks of almost any age.

Uses & applications

Historically used as a source of sulfur and for the production of sulfuric acid. In modern times, it is used in the manufacture of lithium batteries, as a semiconductor material, and as a popular collector's mineral and in costume jewelry (often sold as 'marcasite').

Geological facts

Commonly nicknamed 'Fool's Gold' because its color and metallic luster often misled novice prospectors. It is famous for forming perfect, naturally occurring cubes. Unlike real gold, it is brittle and will shatter if struck, rather than flattening.

Field identification & locations

Identify in the field by its brassy color, hardness (it can scratch glass, while gold cannot), and its greenish-black streak when rubbed on a porcelain plate. It is found worldwide, with major deposits in Spain (Rio Tinto), Peru, and the USA.