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 (often obscured in tumbled pebbles); Cleavage: None/Conchoidal fracture.

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

Identified May 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed from cooling magma or hydrothermal veins. This specific specimen is a water-worn river pebble, shaped by mechanical erosion over hundreds to thousands of years.

Uses & applications

Used in glassmaking, abrasives, and as decorative gravel in landscaping. High-purity quartz is used in electronics for its piezoelectric properties.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is known as rock crystal, but milky quartz gets its color from tiny fluid inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identified by its ability to scratch glass, lack of cleavage, and rounded, smooth surface typical of alluvial transport. Commonly found in riverbeds, beaches, and soil.