Quartzite Pebble

Physical Properties

Hardness: 7 (Mohs scale), Color: White to light grey with small dark inclusions, Luster: Dull to vitreous, Crystal Structure: Hexagonal (microcrystalline), Cleavage: None/Conchoidal fracture, Grainy texture.

Formation & Geological History

Formed from the metamorphism of quartz-rich sandstone. Under intense heat and pressure, quartz grains recrystallize and fuse together. This pebble has been subsequently rounded and smoothed by water transport in a river or coastal environment.

Uses & Applications

Commonly used as decorative landscaping stone, in road construction (as crushed stone), or as a source of silica for glass making. Smooth pebbles are often used in massage therapy and home decor.

Geological Facts

Quartzite is so tough that it often outlasts the surrounding rocks during erosion, often forming the peaks of hills and mountains. It is harder than steel and will easily scratch glass.

Field Identification & Locations

Identify by its extreme hardness (cannot be scratched by a steel knife) and its grainy, 'sugary' appearance under a magnifying lens. Commonly found in riverbeds, glacial deposits, and along beaches. High quartz content makes it very resistant to chemical weathering.

Identified on: 4/16/2026

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