mineral

Pyrite (Fool's Gold) in Matrix

Iron Sulfide (FeS2)

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

Hardness: 6-6
Color: Brass-yellow
Luster: Metallic

Identified June 2, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 6-6.5 on Mohs scale; Color: 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, as an accessory mineral in igneous rocks, and in sedimentary rocks through organic decomposition in oxygen-depleted environments. Often associated with quartz or coal.

Uses & applications

Primarily used in the production of sulfur dioxide for sulfuric acid, in radio receivers (crystal radios), and as a minor ore of iron. Highly valued as a collector's mineral and in costume jewelry.

Geological facts

It earned the nickname 'Fool's Gold' because its metallic luster and brassy color often deceived prospectors into thinking they had found real gold. It is one of the most common sulfide minerals on Earth.

Field identification & locations

Identify by its hardness (it can scratch glass, unlike gold) and its brittle tenacity (it shatters when hit, while gold flattens). Look for cubic or octahedral crystal habits. Commonly found in mines worldwide, particularly in Peru, Spain, and the USA.