mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White to off-white/cream; Luster: Vitreous to waxy when water-worn; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White to off-white/cream
Luster: Vitreous to waxy when water-worn

Identified July 6, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White to off-white/cream; Luster: Vitreous to waxy when water-worn; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or as a primary constituent in igneous rocks like granite. This specific piece is a water-worn river or beach pebble, smoothed over time by mechanical weathering in high-energy aqueous environments.

Uses & applications

Industrial use as a source of silica for glass and electronics; common in landscaping, gravel, and as amateur collector pieces. High-purity quartz is used in oscillators for watches and radios.

Geological facts

Milky quartz gets its cloudy white appearance from millions of tiny fluid inclusions of gas and liquids trapped during the crystal's growth. It is the most common variety of crystalline quartz on Earth.

Field identification & locations

Identified in the field by its hardness (it will easily scratch glass), its white color, and the lack of visible cleavage planes. Found globally in riverbeds, beaches, and mountain scree.