mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent; Luster: Vitreous to waxy (when water-worn); 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 waxy (when water-worn)

Identified June 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specific specimen is a water-worn river or beach pebble, shaped through mechanical erosion over thousands of years.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative gravel or landscaping stones. Milky quartz is also used in inexpensive jewelry and lapidary art.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is traditionally called rock crystal, while this milky variety contains tiny fluid inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and lack of cleavage. Commonly found in riverbeds, beaches, and glacial till globally. Look for the white 'vein' across the surface, which is a common stress fracture filled with more quartz.