mineral

Quartz (Gravel Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White, tan, or milky; Luster: Vitreous to waxy (when weathered); Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: White, tan, or milky
Luster: Vitreous to waxy (when weathered)

Identified June 28, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White, tan, or milky; Luster: Vitreous to waxy (when weathered); Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65.

Formation & geological history

Formed from cooling magma or hydrothermal veins. This specific piece is a highly weathered clast, likely eroded and transported by water, resulting in its small, rounded, pebble-like form.

Uses & applications

Common industrial uses include glass making, electronics, and abrasives. In this size and quality, it serves primarily as construction aggregate or natural river gravel.

Geological facts

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

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and lack of cleavage. Found globally in all geological environments. For collectors, these small common pieces are mostly used for decorative landscaping.