sedimentary

Rounded quartz-rich river pebble

Likely quartzite or weathered sandstone; exact identification requires testing

AI-generated identification · may be incorrect

Tan-brown, dull to slightly waxy luster, fine-grained and strongly rounded; likely Mohs 6–7 if quartzite, or 5–6 if sandstone. No visible crystals or cleavage; specific gravity approximately 2.5–2.7.

Identified September 1, 2026More sedimentary →

Explore Rounded quartz-rich river pebble 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

Formed from quartz-rich sedimentary material, possibly lithified and metamorphosed into quartzite, then rounded by prolonged stream or beach abrasion. Its precise geological age and provenance cannot be determined from the image.

Uses & applications

Commonly used as landscaping stone, decorative pebble, aggregate, and occasionally as a polishing or lapidary rough; little commercial value in this form.

Geological facts

The smooth shape indicates transport in moving water or wave action. A glassy scratch test and lack of gritty grains favor quartzite; visible sand grains and weaker hardness favor sandstone.

Field identification & locations

Look for a sugary interlocking texture, which supports quartzite, versus distinct cemented grains, which indicate sandstone. Common worldwide in riverbeds, gravel deposits, beaches, and glacial tills.