mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 (Mohs scale); Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric/Cubic; Cleavage: Indistinct; Specific Gravity: 4.9–5.2.

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

Identified April 2, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs scale); Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric/Cubic; Cleavage: Indistinct; Specific Gravity: 4.9–5.2.

Formation & geological history

Formed in a variety of geological settings including hydrothermal veins, as an accessory mineral in igneous rocks, in contact metamorphic rocks, and in sedimentary rocks like shale and coal under reducing conditions.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is primarily used in the production of sulfur dioxide for the paper industry and as a collector's specimen. It is sometimes used in inexpensive jewelry (often incorrectly called 'marcasite').

Geological facts

Commonly known as 'Fool's Gold' due to its metallic luster and brassy hue which often confuse novice prospectors. Its name comes from the Greek 'pyr' meaning fire, because it emits sparks when struck by steel.

Field identification & locations

Identify in the field by its cubic crystal habit, high density, and brassy color. Unlike gold, it is brittle and will crush into powder rather than flatten when struck. Found globally, with notable deposits in Spain, Italy, and the USA.