Mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Creamy white to pale yellow; Luster: Vitreous to waxy; Crystal structure: Hexagonal (though not visible in tumbled form); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: Creamy white to pale yellow
Luster: Vitreous to waxy

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids or igneous cooling. This specimen is a 'clastic' pebble, meaning it was weathered from a larger vein and rounded over many years (potentially millions) by water action in a river or coastal environment.

Uses & applications

Common quartz is used in sand for glassmaking, abrasives, and construction. Smooth specimens like this is often used in landscaping, aromatherapy, or as beginner pocket stones for collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. This specific rounded shape is the result of 'abrasion'—the geological process of rocks grinding against each other in moving water.

Field identification & locations

Identify in the field by its hardness (it should scratch glass) and its smooth, water-worn texture. Commonly found in riverbeds, glacial tills, and beaches worldwide. It does not react with acid, distinguishing it from calcite.