sedimentary

Water-worn brown pebble, possibly chert

Likely microcrystalline quartz (SiO₂); exact identification requires examination or testing

AI-generated identification · may be incorrect

Opaque olive-brown, rounded and smooth, with a dull to slightly waxy luster. If chert, hardness is about 7 Mohs, with no visible crystals and no cleavage; the photo alone cannot confirm composition.

Identified September 28, 2026More sedimentary →

Explore Water-worn brown pebble, possibly chert in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Opaque olive-brown, rounded and smooth, with a dull to slightly waxy luster. If chert, hardness is about 7 Mohs, with no visible crystals and no cleavage; the photo alone cannot confirm composition.

Formation & geological history

A pebble’s rounded shape indicates abrasion during transport by water or sediment. Chert forms when silica accumulates and hardens in sedimentary settings; its age and source cannot be determined from the image.

Uses & applications

Small pebbles are used for collecting, landscaping, and crafts; this specimen is not identifiable as gem-grade from the photo.

Geological facts

Color and shape alone are not diagnostic; similar pebbles can be iron-stained quartz, jasper, or other hard rocks.

Field identification & locations

Check for a glassy or waxy surface and hardness: chert can scratch glass, though testing may damage it. Water-worn pebbles occur in riverbeds, beaches, and glacial deposits.