Pyrite

Physical Properties

Hardness: 6-6.5; Color: Pale brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Indistinct; Specific Gravity: 4.8-5.0

Formation & Geological History

Formed in hydrothermal veins, by magmatic segregation, or as an authigenic mineral in sedimentary rocks and metamorphic environments. Found across all geological ages.

Uses & Applications

Historically used for sulfur and sulfuric acid production. Today it is used in jewelry (as marcasite), in paper making, and is a popular collector's mineral.

Geological Facts

Often called 'Fool's Gold' because its color and high specific gravity confuse it with real gold. Unlike gold, it is brittle and leaves a greenish-black streak.

Field Identification & Locations

Identify by its brassy color, cubic crystal habit, and hardness (it scratches copper but gold won't). Common in Peru, Spain, and North America.

Identified on: 5/9/2026

Mode: Standard