mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6–6.5 on the Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (often cubic, pyritohedral, or octahedral); Cleavage: Indistinct; Specific Gravity: 4.8–5.0

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

Identified March 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed in high and low temperature hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks such as shale and coal. It can form in almost any geological age.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is used in the manufacture of lithium batteries, as a semiconductor material, and widely sold as jewelry (marcasite jewelry) and collector specimens.

Geological facts

Commonly known as 'Fool's Gold' because its color and high density lead novice gold seekers to mistake it for the precious metal. When struck against steel or flint, it produces sparks, hence its name derived from the Greek word 'pyr' meaning fire.

Field identification & locations

Identify in the field by its brittle nature (gold is malleable), brassy yellow color, and green-black streak when rubbed on a porcelain plate. Common locations include Peru, Spain, Italy, and various regions across the United States. Collectors should look for well-defined cubic crystals.