Quartz (Gravel Pebble)

Physical Properties

Hardness: 7 on Mohs scale; Color: Colorless to translucent; Luster: Vitreous/Glassy; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & Geological History

Forms in nearly all geological environments, particularly igneous and metamorphic rocks, through crystallization from magma or hydrothermal precipitate. Found globally in all geological ages.

Uses & Applications

Raw industrial quartz is used in glassmaking, abrasives, and electronics (piezoelectric properties). Rounded pebbles are used in landscaping and as aggregate in construction.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Small, rounded pebbles like this are often the result of long-term weathering and transport by water in rivers or beaches.

Field Identification & Locations

Identify by its hardness (it can scratch glass), its lack of cleavage, and glassy appearance. Common in riverbeds, beaches, and soil worldwide.

Identified on: 5/11/2026

Mode: Standard