mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Tan to off-white; Luster: Waxy to vitreous; Crystal Structure: Trigonal (often microcrystalline in river pebbles); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Tan to off-white
Luster: Waxy to vitreous

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed through crystallization of igneous rocks or hydrothermal veins. This specific specimen is a river-worn pebble, having been rounded by the mechanical action of water and abrasive sediments over decades or centuries.

Uses & applications

Quartz is used extensively in glassmaking, electronics (piezoelectric properties), abrasives, and as ornamental stones or landscaping mulch.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to chemical and physical weathering, which is why it commonly survives as pebbles long after other minerals have decomposed.

Field identification & locations

Identify in the field by its hardness (it should scratch glass),Lack of cleavage, and smooth rounded surface if found in riverbeds. It is found globally in almost all geological environments.