Quartz (River Pebble)

Physical Properties

Hardness: 7 (Mohs scale), Color: Creamy white to translucent beige, Luster: Vitreous to waxy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.65

Formation & Geological History

Formed from silica-rich hydrothermal solutions or as a primary constituent in igneous rocks like granite. This specific specimen is a 'river pebble,' meaning it has been mechanically weathered and rounded by the action of moving water over a long period (thousands of years).

Uses & Applications

Industrial uses include glass making, electronics, and abrasives. In this rounded form, they are commonly used for landscaping, decorative garden stones, or as tumbling media for rock polishers.

Geological Facts

Quartz is one of the most abundant and durable minerals in the Earth's crust, which is why it often survives long-distance transport in rivers while softer minerals break down. It is piezoelectric, meaning it can generate an electric charge under mechanical stress.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass but cannot be scratched by a steel knife) and lack of cleavage. Common in riverbeds, beaches, and glacial deposits worldwide.

Identified on: 4/15/2026

Mode: Standard