sedimentary

Rounded quartz-rich pebble, possibly chert or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂) or quartzite

AI-generated identification · may be incorrect

Brown to tan, fine-grained, dull-to-waxy luster, rounded and water-worn; estimated Mohs hardness 6.5–7, with no visible cleavage. The glossy surface appears wet or polished, and the image is insufficient to confirm texture or composition.

Identified September 21, 2026More sedimentary →

Explore Rounded quartz-rich pebble, possibly chert or quartzite 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

Likely formed as a siliceous rock and rounded by stream or beach transport; quartz-rich sedimentary materials may date from Precambrian to much younger deposits depending on source.

Uses & applications

Usually collected as a common pebble, lapidary rough, or tumbled stone; quartzite and chert can be used as aggregate or durable construction stone.

Geological facts

A steel knife should not easily scratch it, while quartz or a glass plate may scratch softer look-alikes. Strong fizz with dilute hydrochloric acid would suggest carbonate rock instead, though no fizz is expected for quartz-rich material.

Field identification & locations

Common in gravel bars, riverbeds, beaches, and glacial deposits worldwide. A fresh fracture, streak test, hardness test, and close inspection for grain boundaries are needed to distinguish quartzite from chert or jasper.