mineral

Pyrite in Matrix (likely Quartz or Schist matrix)

Iron Sulfide (FeS2)

Hardness: 6-6.5 (Mohs); Color: Brass-yellow or dull gold; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Poor/Indistinct; Specific Gravity: 4.9-5.2.

Hardness: 6-6
Color: Brass-yellow or dull gold
Luster: Metallic

Identified April 16, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs); Color: Brass-yellow or dull gold; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Poor/Indistinct; Specific Gravity: 4.9-5.2.

Formation & geological history

Forms in hydrothermal veins, as an accessory mineral in igneous rocks, and in sedimentary environments under reducing conditions. This specimen appears to be from a metamorphic or hydrothermal context due to the weathered matrix.

Uses & applications

Primarily used for the production of sulfur dioxide (sulfuric acid) in industry. Also a major source of iron, though difficult to extract. Popular as a collector's 'Fool\'s Gold' and occasionally used in jewelry (marcasite jewelry).

Geological facts

Often called 'Fool's Gold' because its color and metallic luster lead beginner prospectors to mistake it for real gold. Unlike gold, pyrite is brittle and leaves a black or greenish-black streak when rubbed on a porcelain plate.

Field identification & locations

Identify by its hardness (will scratch glass, gold will not), its brittle nature when crushed, and its greenish-black streak. Commonly found in mine tailings, quarries, and mountain regions worldwide.

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

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral