mineral

Quartz Pebble

Quartz (Silicon Dioxide - SiO2)

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

Identified April 22, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky white to tan; Luster: Vitreous to waxy (when water-worn); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal fluids or magma. This specific specimen has been chemically and mechanically weathered, typically in a fluvial (river) or marine (beach) environment, resulting in its smooth, rounded 'pebble' shape.

Uses & applications

River stones are used in landscaping, as aquarium decor, and in construction as aggregate. Higher-grade milky quartz is used as an abrasive or in glass manufacturing.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. White quartz is often called 'milky quartz' due to 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 steel) and lack of cleavage. It is extremely common in riverbeds and on beaches worldwide. This shape suggests it has traveled a long distance from its source rock.