Pyrite

Physical Properties

Hardness: 6-6.5 Mohs; Color: Pale brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Indistinct; Specific Gravity: 4.9-5.2.

Formation & Geological History

Forms in a variety of geological settings, including hydrothermal veins, as an accessory mineral in igneous rocks, and in sedimentary environments like coal beds and shales where reducing conditions are present.

Uses & Applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used primarily in jewelry (as marcasite), electronics, and as a popular collector specimen.

Geological Facts

Commonly known as Fool's Gold due to its resemblance to precious metals. During WWII, it was used as a source of iron and sulfur when other ores were scarce. It can actually contain trace amounts of real gold.

Field Identification & Locations

Identify by its hardness (will scratch glass, unlike gold) and its greenish-black streak when rubbed on a porcelain plate. Found globally in locations like Spain, Peru, and the USA.

Identified on: 5/13/2026

Mode: Standard