mineral

Milky Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White, translucent, or cloudy reddish-brown; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White, translucent, or cloudy reddish-brown
Luster: Vitreous to greasy

Identified July 5, 2026More mineral →

Explore Milky Quartz Pebble in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed from the crystallization of silica-rich hydrothermal solutions in veins or as a constituent of igneous rocks like granite. This specimen appears water-worn, likely from a stream or alluvial deposit.

Uses & applications

Primarily used as a source of silica for semiconductors, glass making, and as an abrasive. Polished pebbles are common in decorative landscaping and aquarium gravel.

Geological facts

The milky appearance is caused by tiny inclusions of gas or liquid trapped during the crystal's growth. It is one of the most common minerals in Earth's crust.

Field identification & locations

Identified by its hardness (scratches glass), lack of cleavage, and waxy luster when tumbled. Commonly found in riverbeds, glacial deposits, and mountain outcrops.

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

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock

Granite

Granite (Phaneritic intrusive igneous rock)

igneous