Pyrite (Fool's Gold)

Physical Properties

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

Formation & Geological History

Forms in hydrothermal veins, by magmatic segregation, and as an authigenic mineral in sedimentary rocks. Can be found in rocks from all geological ages.

Uses & Applications

Historically used to create sparks for firearms. Today used for the production of sulfuric acid, as a semiconductor in solar cells, and as a popular collector's mineral and in costume jewelry.

Geological Facts

Nicknamed 'Fool's Gold' because its color often confused prospectors. Despite the name, it occasionally contains small amounts of actual gold. It is the most common sulfide mineral on Earth.

Field Identification & Locations

Identify by its brittle nature (gold is malleable), black/greenish streak on a porcelain plate, and distinct cubic crystal habits. Found globally with major deposits in Spain, Peru, and the USA.

Identified on: 5/17/2026

Mode: Standard