Quartzite Pebble

Physical Properties

Hardness: 7 on Mohs scale; Color: Tan to pale orange-brown; Luster: Vitreous to dull (when weathered); Crystal structure: Hexagonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.63–2.65

Formation & Geological History

Formed through the metamorphism of quartz sandstone under high heat and pressure, causing the original quartz grains to recrystallize and fuse together. This specimen appears water-worn from a river or beach environment.

Uses & Applications

Used as a decorative aggregate in landscaping, as a building material in road construction, and occasionally for lapidary work or as polishing stones.

Geological Facts

Quartzite is so tough that it often outlasts the surrounding rocks in a landscape, forming resistant ridges. It is often confused with marble but can be distinguished because quartzite will not react with acid and can scratch glass.

Field Identification & Locations

Identify in the field by its extreme hardness (scratching glass or steel) and sugary texture. Commonly found in riverbeds, glacial deposits, and mountain ranges globally.

Identified on: 4/17/2026

Mode: Standard