Quartzite Pebble

Physical Properties

Hardness: 7 (Mohs scale); Color: White, grey, reddish-brown (from iron oxidation); Luster: Vitreous to dull; Crystal structure: Trigonal (granular); Cleavage: None; Specific gravity: ~2.6-2.7

Formation & Geological History

Formed through the metamorphism of quartz sandstone. Intense heat and pressure cause quartz grains to recrystallize and fuse together. This pebble has been subsequently water-worn and smoothed by river or glacial transport.

Uses & Applications

Used as a decorative gravel, in landscaping, as a construction aggregate, and occasionally in the production of glass or silicone.

Geological Facts

Quartzite is so tough that it often outlasts the surrounding softer rocks, eventually forming high ridges or resistant pebbles found far from their original source. Unlike sandstone, quartzite fractures across the sand grains rather than around them.

Field Identification & Locations

Identify by its extreme hardness (cannot be scratched by steel) and granular texture. Commonly found in riverbeds, till deposits, and mountain ranges. Collectors look for unique banding or color patterns.

Identified on: 4/25/2026

Mode: Standard