sedimentary

Likely quartz-rich sedimentary pebbles

Quartz arenite or chert-like siliceous rock; exact identification is uncertain from the photograph

AI-generated identification · may be incorrect

Pale gray-white, dull to subtly sugary/granular luster, irregular rounded shapes, and no visible crystals or cleavage. Likely Mohs hardness about 6–7 if quartz-rich; specific gravity approximately 2.6.

Identified September 4, 2026More sedimentary →

Explore Likely quartz-rich sedimentary pebbles in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Probably naturally weathered and water-worn fragments of silica-rich sedimentary rock, potentially formed from lithified sand or microcrystalline silica. Their geological age cannot be determined visually.

Uses & applications

Common material has little commercial value; similar quartz-rich rocks may be used as aggregate, landscaping stone, or decorative tumbled specimens.

Geological facts

The rough, granular texture suggests quartz sandstone more than a crystalline quartz mineral, while the lighter piece could also be a weathered chert or quartzite fragment.

Field identification & locations

Look for a glassy fracture, inability to scratch with a steel knife, and little or no reaction to dilute hydrochloric acid; sandstone usually shows visible sand grains, whereas quartzite breaks across fused grains. Common in river gravel, beaches, and weathered outcrops.