mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to off-white; Luster: Vitreous to waxy (especially when water-worn); Crystal structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to off-white
Luster: Vitreous to waxy (especially when water-worn)

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Quartz is one of the most abundant minerals in the Earth's crust. This specimen is a water-worn river pebble, shaped by the abrasive action of water and sediments over time. It can be millions of years old, originating from igneous veins or metamorphic rocks.

Uses & applications

Used in construction, glass manufacturing, abrasives, and as decorative landscape gravel. High-purity quartz is used in electronics for its piezoelectric properties.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but impurities create various colors like amethyst, citrine, and rose quartz. Rounded pebbles like this are often referred to as 'river stones'.

Field identification & locations

Identify in the field by its hardness (it should scratch glass) and lack of visible cleavage planes. It is commonly found in river beds, beaches, and glacial deposits worldwide.