mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Tan, white, or translucent; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Tan, white, or translucent
Luster: Vitreous to waxy

Identified June 22, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Tan, white, or translucent; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed from molten magma or in hydrothermal veins. This specific specimen is a water-worn pebble likely eroded from its source rock and transported by water, rounding its edges over thousands of years.

Uses & applications

Common quartz is used in construction as aggregate, in glassmaking, and in electronics for its piezoelectric properties. Smooth pebbles are often used in landscaping or as aquarium gravel.

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 often remains as pebbles after other minerals have decomposed.

Field identification & locations

Identify in the field by its hardness (it can scratch glass) and lack of cleavage. It is found globally in riverbeds, beaches, and soil. To identify, look for the waxy luster and smooth, rounded surface characteristic of alluvial transport.