Pyrite (Fool's Gold)

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

Formed in high and low-temperature hydrothermal veins, by magmatic segregation, and as an accessory mineral in igneous rocks, as well as in sedimentary rocks like shale and coal.

Uses & Applications

Used in the production of sulfur dioxide for sulfuric acid, in the paper industry, and popular as a decorative specimen for mineral collectors and in jewelry.

Geological Facts

Known as Fool's Gold due to its resemblance to gold, though it is much harder and more brittle. It can create sparks when struck against steel, leading to its name derived from the Greek word 'pyr' meaning fire.

Field Identification & Locations

Identify by its metallic luster, brassy color, and greenish-black streak (unlike gold which has a golden streak). Common in Peru, Spain, Italy, and the US.

Identified on: 5/7/2026

Mode: Standard