Rock Identifier
Pyrite (Fool's Gold) (Iron Pyrite (FeS2)) — mineral
mineral

Pyrite (Fool's Gold)

Iron Pyrite (FeS2)

Hardness: 6.0-6.5 Mohs. Color: Brass-yellow to pale metallic gold. Luster: Metallic. Crystal structure: Isometric/cubic. Cleavage: Indistinct. Specific gravity: 4.95-5.10. Streak: Greenish-black to brownish-black.

Hardness
6
Color
Brass-yellow to pale metallic gold
Luster
Metallic
Identified More mineral
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Physical properties

Hardness: 6.0-6.5 Mohs. Color: Brass-yellow to pale metallic gold. Luster: Metallic. Crystal structure: Isometric/cubic. Cleavage: Indistinct. Specific gravity: 4.95-5.10. Streak: Greenish-black to brownish-black.

Formation & geological history

Forms in hydrothermal veins, metamorphic rocks, and sedimentary rocks through reaction between iron and sulfur fluids. Common in volcanic sulfide deposits as found in the East African Rift region (Ethiopia).

Uses & applications

Historically used to produce sulfuric acid and sulfur dioxide. Major industrial source of sulfur; occasionally an ore of gold when auriferous. Used in jewelry (marcasite jewelry), educational kits, and rock collections.

Geological facts

Nicknamed 'Fool's Gold' due to its superficial similarity to real gold. Unlike gold, pyrite is hard enough to scratch glass, brittle (shatters under impact), and leaves a dark greenish-black streak instead of a yellow streak.

Field identification & locations

Identified by brassy metallic luster, high hardness, brittleness, and dark streak. Commonly found in association with quartz, calcite, chalcopyrite, and sphalerite. Found in volcanic and metamorphic terranes across Ethiopia.