mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent; Luster: Vitreous to greasy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Milky white to translucent
Luster: Vitreous to greasy

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky white to translucent; Luster: Vitreous to greasy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Forms in hydrothermal veins or as a primary constituent in igneous rocks like granite. This specific specimen has been rounded and smoothed by water erosion through transport in a river or beach environment.

Uses & applications

Used in glass making, abrasive manufacturing, electronics (due to piezoelectric properties), and as decorative landscaping stone or tumbled pocket stones.

Geological facts

The milky appearance is caused by millions of tiny fluid inclusions of gas and/or liquid trapped during the crystal's growth. It is one of the most abundant minerals on Earth's crust.

Field identification & locations

Identify by its hardness (it will scratch glass), its white 'milky' color, and lack of cleavage. Often found in riverbeds, glacial deposits, and beaches globally.