mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

AI-generated identification · may be incorrect

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

Hardness: 6-6
Color: Pale brass-yellow
Luster: Metallic

Identified April 10, 2026More mineral →

Explore Pyrite (Fool's Gold) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

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, metamorphic, and sedimentary rocks (including coal beds and carbonate rocks).

Uses & applications

Major ore for sulfur/sulfuric acid; used in radio receivers (crystal detectors) historically; popular for jewelry (often called marcasite in the trade) and as a collector's specimen.

Geological facts

Known as 'Fool's Gold' because its color and metallic luster often misled prospectors. Unlike gold, pyrite is brittle and leaves a greenish-black streak when rubbed on a porcelain plate.

Field identification & locations

Identify by its brassy color, cubic crystal habits, and high hardness (it can scratch glass). Found globally, with famous deposits in Spain, Peru, Italy, and the USA.