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 or pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.9-5.2.

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

Identified March 4, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in a variety of geological settings including hydrothermal veins, sedimentary rocks through biological activity in oxygen-poor environments, and as an accessory mineral in igneous rocks. It has formed throughout Earth's history across all geological eras.

Uses & applications

Historically used for the production of sulfuric acid and sulfur. In the past, it was used in wheel-lock firearms to create sparks. Today, it is primarily used in jewelry (as 'marcasite' in the trade), as a collector's mineral, and in some types of lithium batteries.

Geological facts

Pyrite is nicknamed 'Fool's Gold' because its color and metallic luster often led prospectors to mistake it for real gold. Unlike real gold, which is soft and malleable, pyrite is brittle and will shatter if struck. It is also a semiconductor mineral.

Field identification & locations

Identify in the field by its brassy color, cubic crystal habit, and its greenish-black streak (real gold has a golden-yellow streak). It is commonly found worldwide, notably in Spain, Italy, and various locations across the United States. Collectors look for sharp, mirror-like cubic faces.