mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to off-white; Luster: Vitreous to waxy; Structure: Hexagonal/Trigonal; no cleavage; Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Milky white to off-white
Luster: Vitreous to waxy

Identified April 9, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky white to off-white; Luster: Vitreous to waxy; Structure: Hexagonal/Trigonal; no cleavage; Conchoidal fracture; Specific gravity: 2.65.

Formation & geological history

Formed through the cooling of magma or precipitation from hydrothermal veins. This specific specimen is a tumbled pebble, meaning it was weathered from its original source and rounded by the abrasive action of water (river or beach) over many years.

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), construction aggregates, and as decorative landscaping stones or jewelry beads.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. These rounded white pebbles are often called 'lucky stones' or 'moon stones' by children though they are geologically common milky quartz.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel), its lack of cleavage, and its smooth, rounded 'water-worn' texture. Found globally in riverbeds and coastal regions.