Pyrite

Physical Properties

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow with a metallic luster; Crystal structure: Isometric (often cubic or pyritohedral); Cleavage: Indistinct; Specific gravity: 4.9-5.2.

Formation & Geological History

Forms in diverse environments including magmatic segregation, hydrothermal veins, and as a common authigenic mineral in sedimentary rocks like shales. It can form across all geological ages.

Uses & Applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the production of lithium batteries, as a semiconductor material, and as collector specimens.

Geological Facts

Commonly known as Fool's Gold due to its metallic luster and yellow hue. It was used in early firearms like the wheel-lock to create sparks to ignite gunpowder.

Field Identification & Locations

Identify by its hardness (it can scratch glass, unlike gold) and its greenish-black streak. Commonly found in quartz veins or dark sedimentary rocks. Collectors look for well-defined cubic crystals.

Identified on: 5/7/2026

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