mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale; Color: Milky white to translucent; Luster: Vitreous to waxy (when tumbled); Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: Milky white to translucent
Luster: Vitreous to waxy (when tumbled)

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Usually forms in igneous or metamorphic environments through hydrothermal precipitation or crystallization from cooling magma. This specific specimen has been significantly eroded and rounded by water transport in a river or coastal environment.

Uses & applications

Common quartz is used industrially in glassmaking, abrasives, and as a component in concrete. Tumbled stones like this are used in landscaping, aquarium decor, and as 'worry stones' or beginner collection pieces.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Because it is chemically stable and physically hard, it persists as pebbles and sand long after other minerals have weathered away.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife and its lack of flat cleavage planes. It is found globally in riverbeds, beaches, and glacial deposits. For collectors, it is a staple introductory specimen.