mineral

Pyrite (“fool’s gold”) specimens

Pyrite, iron disulfide (FeS₂)

AI-generated identification · may be incorrect

Brassy yellow metallic luster; commonly cubic, pyritohedral, or granular crystals with poor cleavage and conchoidal-to-irregular fracture. Mohs hardness 6–6.5; specific gravity about 5.0; the visible pieces appear natural or lightly prepared crystalline masses.

Identified September 7, 2026More mineral →

Explore Pyrite (“fool’s gold”) specimens in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Forms in hydrothermal veins, sedimentary rocks, coal beds, and metamorphic environments when iron and sulfide combine under reducing conditions. Individual crystals may span many geologic ages, from Precambrian deposits to modern hydrothermal systems.

Uses & applications

Used historically as a sulfur and iron source, and occasionally for sulfuric-acid production; today it is mainly a collector mineral and decorative specimen. It is not a valuable gold substitute, though some pyrite contains trace recoverable gold.

Geological facts

Its metallic gold color and density led to the name “fool’s gold.” Unlike gold, pyrite is brittle, can tarnish or oxidize, and produces a dark streak rather than a yellow one.

Field identification & locations

Identify by brassy color, blocky crystal faces, high hardness, and a dark greenish-black streak; a steel file generally does not scratch it easily. Common localities include Spain, Peru, Italy, the United States, China, and Russia.