mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs), Color: Translucent grey/brown (smoky variety), Luster: Vitreous to waxy (water-worn), Crystal System: Hexagonal (trigonal), No cleavage, Conchoidal fracture.

Identified July 19, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs), Color: Translucent grey/brown (smoky variety), Luster: Vitreous to waxy (water-worn), Crystal System: Hexagonal (trigonal), No cleavage, Conchoidal fracture.

Formation & geological history

Formed in various geological environments but predominantly in igneous and metamorphic rocks; this specific specimen has been smoothed and rounded by long-term water erosion in a river or beach environment.

Uses & applications

Used in construction aggregate, landscaping, glass making, and as decorative river stones. High-purity quartz is used in electronics.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. These rounded smooth pebbles are often called 'river rocks' and can survive millions of years of erosion due to their high hardness.

Field identification & locations

Identify by its hardness (scratches glass), translucent appearance, and lack of visible grains. Commonly found in riverbeds, glacial deposits, and coastal beaches.