mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to light tan; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Milky white to light tan
Luster: Vitreous to waxy

Identified June 21, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky white to light tan; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specific specimen is a water-worn pebble, likely eroded from a larger vein and smoothed over centuries by river or coastal wave action.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative landscaping stones or aquarium gravel.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is colorless, but impurities create a vast range of varieties like amethyst and citrine.

Field identification & locations

Identify by its hardness (it will scratch glass) and lack of cleavage. Commonly found in riverbeds, beaches, and mountainous regions worldwide. For collectors, look for translucent rounded edges.