mineral

Milky Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Opaque white to light gray; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Opaque white to light gray
Luster: Vitreous to greasy

Identified July 16, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white to light gray; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed from hydrothermal solutions or within igneous pegmatites. This specific specimen is a water-worn river pebble, likely millions of years old, weathered and transported by water action.

Uses & applications

Commonly used as a decorative ground cover, in construction aggregate, and as a source of silica for glass manufacturing and electronics.

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 in the field by its hardness (it will scratch glass), its lack of cleavage, and its characteristic waxy or glassy luster. This type of pebble is ubiquitous in stream beds and glacial deposits.