mineral

Milky Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to opaque; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: White to opaque
Luster: Vitreous to greasy

Identified June 1, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to opaque; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Formation & geological history

Formed through the cooling of silica-rich hydrothermal fluids in veins or pegmatites. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth.

Uses & applications

Used in glassmaking, as an abrasive, in electronics for its piezoelectric properties, and widely in landscaping or as a collector's base specimen.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is the most common variety of crystalline quartz found in nature.

Field identification & locations

Identified in the field by its hardness (scratches glass), lack of cleavage, and white opaque color. Usually found as rounded pebbles in stream beds or as veins in metamorphic and igneous rocks.

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