sedimentary

Weathered quartz-rich river pebble

Likely quartzite or siliceous sandstone; exact identification requires testing

AI-generated identification · may be incorrect

Hardness approximately 6.5–7 Mohs if quartzite, with a dull to slightly vitreous luster, rounded shape, gray-beige color, and rusty-brown iron-oxide staining. Massive, non-cleavable texture is visible; composition appears predominantly microcrystalline quartz with possible feldspar or cement.

Identified August 29, 2026More sedimentary →

Explore Weathered 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

Likely formed from silica-rich sediment that lithified and possibly metamorphosed into quartzite, then was rounded by stream or beach transport; its precise geological age and source cannot be determined from the image. Brown areas are probably weathering or iron staining.

Uses & applications

Common quartzite and sandstone are used as aggregate, paving, building stone, and decorative rock; this small specimen has mainly educational or casual collecting value rather than jewelry value.

Geological facts

The smooth, rounded surface indicates prolonged abrasion in moving water or surf. A steel nail should not easily scratch quartzite, while a streak test on unglazed porcelain may help distinguish iron staining from softer minerals.

Field identification & locations

Look for a gritty or fused quartz texture, absence of obvious cleavage, and resistance to scratching; vinegar will not fizz unless carbonate cement is present. Common in river gravels, beaches, glacial deposits, and eroding quartz-rich formations.