mineral

Pyrite in Quartz

Iron Disulfide (FeS2) in Silicon Dioxide (SiO2)

Hardness: 6-6.5 (Pyrite) / 7 (Quartz); Color: Brass-yellow (metallics), white to grey (matrix); Luster: Metallic to vitreous; Crystal Structure: Isometric/Cubic (Pyrite), Trigonal (Quartz); Specific Gravity: 4.9-5.2.

Hardness: 6-6
Color: Brass-yellow (metallics), white to grey (matrix)
Luster: Metallic to vitreous

Identified June 1, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins and sedimentary environments through the precipitation of iron-rich fluids in the presence of sulfur. Often found in metamorphic rocks and associated with gold deposits.

Uses & applications

Primarily used as an ore of sulfur and for the production of sulfuric acid; used in jewelry as 'marcasite' and highly valued as a collector's specimen.

Geological facts

Pyrite is famously known as 'Fool's Gold' because its color and luster often deceive novice prospectors, although it is much harder and more brittle than real gold.

Field identification & locations

Identify by its brassy color, cubic crystal habit, and blackish-green streak. Common in mines worldwide, particularly in Peru, Spain, and the USA. Collectors look for well-defined cubes or pyritohedrons.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic