mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

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

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

Identified June 8, 2026More mineral →

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Physical properties

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

Formation & geological history

Quartz forms in a wide variety of environments, most commonly from the cooling of magma or by hydrothermal precipitation in veins. These pebbles are typically worn down into rounded shapes by water transport in rivers or coastal environments over thousands of years.

Uses & applications

Used in the manufacturing of glass, abrasives, electronics (due to piezoelectric properties), and as a common decorative aggregate in landscaping and construction.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. The 'milky' appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify by its white color, inability to be scratched by a steel knife, and lack of cleavage. It is found globally in riverbeds, beaches, and glacial deposits. Check for a characteristic glassy luster on a fresh break.