Quartz Pebble (Water-worn Quartzite)

Physical Properties

Hardness: 7 (Mohs scale); Color: Tan, white, and translucent; Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture.

Formation & Geological History

Formed from the recrystallization of quartz-rich sandstone under intense heat and pressure (metamorphism). The rounded shape is the result of mechanical weathering and erosion, typically in a high-energy river or beach environment.

Uses & Applications

Used as decorative garden stones, in industrial glass making, as a source for silicon, and occasionally in river-stone jewelry.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. These smooth pebbles are often found in 'conglomerate' rock layers that represent ancient riverbeds.

Field Identification & Locations

Identify in the field by its hardness (it can scratch glass) and its smooth, rounded exterior with a waxy surface. Commonly found in riverbeds, gravel pits, and along shorelines worldwide.

Identified on: 4/25/2026

Mode: Standard