Pyrite

Physical Properties

Hardness: 6-6.5 Mohs; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (often cubic or pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.8-5.0.

Formation & Geological History

Formed in a variety of geological settings, including hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic deposits, and in sedimentary rocks (like shale or coal) through the reduction of sulfates by bacteria.

Uses & Applications

Historically used as a source of sulfur and sulfuric acid. Today it is used in the production of lithium-sulfur batteries, as a flux in glassmaking, and extensively as a decorative mineral for jewelry and specimen collecting.

Geological Facts

Commonly known as 'Fool's Gold' because its color and metallic luster often tricked novice prospectors. It is one of the few minerals that can create a spark when struck against steel, a property used in early firearms like wheellocks.

Field Identification & Locations

Identify in the field by its brassy color, high hardness (it cannot be scratched by a copper penny or steel knife), and its greenish-black streak (real gold has a yellow streak). Found worldwide, with famous deposits in Spain, Peru, and the USA.

Identified on: 4/23/2026

Mode: Standard