Quartz Pebble

Physical Properties

Hardness: 7 (Mohs scale); Color: Milky white to translucent; Luster: Vitreous/waxy; Crystal Structure: Trigonal/Hexagonal (cryptocrystalline in this form); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & Geological History

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specific specimen is 'water-worn,' meaning it has been eroded and smoothed by the action of water in a river or coastal environment over thousands of years.

Uses & Applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative gravel or landscaping stones.

Geological Facts

Quartz is the second most abundant mineral in the Earth's continental crust. It is extremely resistant to chemical weathering, which is why quartz pebbles often remain long after other minerals have eroded into silt or clay.

Field Identification & Locations

Identify in the field by its hardness (it will easily scratch glass) and its lack of cleavage. Look for a waxy appearance and a lack of reaction to acid. Common in riverbeds, beaches, and gravel pits globally.

Identified on: 4/19/2026

Mode: Standard