mineral

Pyrite and Quartz Agglomerate

Iron Sulfide (FeS2) with Silicon Dioxide (SiO2)

Hardness: 6-6.5 (Pyrite) and 7 (Quartz); Color: Metallic gold/brass with white/clear translucency; Luster: Metallic and vitreous; Crystal structure: Isometric (cubes) and Trigonal; Cleavage: Indistinct; Specific gravity: 4.9-5.2.

Hardness: 6-6
Color: Metallic gold/brass with white/clear translucency
Luster: Metallic and vitreous

Identified June 24, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, as an accessory mineral in igneous rocks, and in sedimentary environments through precipitation in low-oxygen, sulfur-rich conditions.

Uses & applications

Primarily collected as mineral specimens; Pyrite is historically used for sulfur dioxide production and as a gemstone (marcasite jewelry), while Quartz is used in electronics and glass.

Geological facts

Commonly known as Fool's Gold due to its resemblance to precious metal. Pyrite can actually spark when struck against steel, which led to its name derived from the Greek word for fire.

Field identification & locations

Identify by its metallic luster, greenish-black streak (on a streak plate), and brittle nature compared to malleable gold. Found globally in mining districts.

Other mineral specimens

See all

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