mineral

Pyrite in Matrix

Iron Sulfide (FeS2)

Hardness: 6-6.5 Mohs; Color: brass-yellow, metallic gold; Luster: metallic; Crystal structure: isometric (cubic); Cleavage: indistinct; Specific gravity: 4.9–5.2.

Hardness: 6-6
Color: brass-yellow, metallic gold
Luster: metallic

Identified May 28, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs; Color: brass-yellow, metallic gold; Luster: metallic; Crystal structure: isometric (cubic); 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 by segregation from magmas. It also forms in sedimentary rocks via bacterial reduction of sulfates.

Uses & applications

Primarily used as an ore of sulfur and for the production of sulfuric acid. In jewelry, it is often marketed as 'Marcasite'. It is also a very popular specimen for mineral collectors.

Geological facts

Known as 'Fool's Gold' because of its visual similarity to real gold. Unlike gold, pyrite is brittle and will shatter if struck, while gold is malleable.

Field identification & locations

Identify by its metallic luster and brassy color. It has a greenish-black streak when rubbed on a porcelain plate. Commonly found in quartz veins and sedimentary shales worldwide.