Pyrite

Physical Properties

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

Formation & Geological History

Formed in high and low-temperature hydrothermal veins, by magmatic segregation, and as an accessory mineral in igneous, metamorphic, and sedimentary rocks. It is present in rocks of all geological ages.

Uses & Applications

Used primarily as an ore of sulfur and for the production of sulfuric acid. In the past, it was used in firearms and jewelry (often called 'marcasite'). Today, it is popular for metaphysical use and as a collector mineral.

Geological Facts

Commonly known as 'Fool's Gold' because its color resembles gold. Unlike gold, it is brittle and will shatter if struck, and it is hard enough to scratch glass.

Field Identification & Locations

Identify by its metallic luster, 'fool's gold' color, and greenish-black streak (real gold has a yellow streak). Found worldwide, with notable deposits in Spain, Italy, Peru, and the USA.

Identified on: 4/16/2026

Mode: Standard