Quartz pebble

Physical Properties

Hardness: 7 (Mohs scale); Color: White/Translucent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Formed from cooling magma or precipitation in hydrothermal veins. This specific specimen appears to be a water-worn fragment, likely eroded from a larger vein and rounded by transport in water.

Uses & Applications

Source of silica for glassmaking, abrasives, quartz watches (piezoelectric properties), and aggregate in landscaping/construction.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It is extremely resistant to chemical and physical weathering, which is why it is the primary component of most beach sand.

Field Identification & Locations

Identify in the field by its ability to scratch glass, its lack of cleavage (it breaks into curved shards), and its resistance to acid. Widely found in riverbeds, beaches, and soil globally.

Identified on: 4/21/2026

Mode: Standard