mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (often cubic, octahedral, or pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.9–5.2.

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

Identified March 11, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed in high and low-temperature hydrothermal veins, as an accessory mineral in igneous rocks, in metamorphic rocks, and as a replacement mineral in sedimentary rocks. It is found in geological formations spanning from the Archean Eon to the present.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the production of lithium batteries, as a semiconductor material, and widely collected as a decorative mineral or used in inexpensive 'marcasite' jewelry.

Geological facts

Known as 'Fool's Gold' because its color and high specific gravity lead novice prospectors to mistake it for gold. It can actually spark when struck against steel, which led to its name derived from the Greek word 'pyr' meaning fire.

Field identification & locations

Identify in the field by its brittle nature (gold is malleable) and its blackish-green streak on a porcelain plate (gold has a yellow streak). Commonly found in Peru, Spain, Italy, and the USA. Collectors look for well-defined cubic crystals.