Pyrite

Physical Properties

Hardness: 6-6.5 Mohs; Color: Brass-yellow; Luster: Metallic; Crystal Structure: Isometric/Cubic; Cleavage: Poor/Indistinct; Specific Gravity: 4.9-5.2

Formation & Geological History

Forms in diverse environments including igneous, metamorphic, and sedimentary settings via hydrothermal activity, magmatic segregation, or chemical precipitation in low-oxygen environments.

Uses & Applications

Used as an ore of sulfur and sulfuric acid, in costume jewelry, and as a popular collector specimen. Historically used for making fire and in early radio receivers.

Geological Facts

Commonly known as 'Fool's Gold' due to its resemblance to precious metals. Unlike gold, it is brittle and leaves a greenish-black streak when rubbed on a porcelain plate.

Field Identification & Locations

Identify by its metallic brass color, hard/brittle texture (cannot be scratched by a copper penny), and cubic habit. Commonly found in Spain, Peru, Italy, and the USA.

Identified on: 4/13/2026

Mode: Standard