Pyrite

Physical Properties

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow; Luster: Metallic; Crystal Structure: Isometric (cubes, pyritohedrons); Cleavage: Indistinct; Specific Gravity: 4.9-5.2

Formation & Geological History

Forms in diverse geological environments: hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks like shale and coal. It forms across all geological ages.

Uses & Applications

Primarily used as a source of sulfur for making sulfuric acid. Historically used for firearms ignition (wheel-locks) and as a semiconductor. Used in jewelry (marcasite jewelry) and as popular collector specimens.

Geological Facts

Commonly known as 'Fool's Gold' because its color and metallic luster often misguide novice prospectors. It is the most common sulfide mineral and can produce sparks when struck against steel.

Field Identification & Locations

Identify in the field by its brassy color, cubic crystal habit, and green-to-black streak (real gold has a yellow streak). Commonly found worldwide, with famous deposits in Spain (Rio Tinto) and Peru.

Identified on: 5/13/2026

Mode: Standard