metamorphic

Polished brown river pebble, likely iron-stained quartzite

Quartz-rich quartzite (SiO₂), with possible iron-oxide staining

AI-generated identification · may be incorrect

Smooth, rounded, opaque brown-gold surface with a subdued polish. Quartz has Mohs hardness 7, vitreous luster when freshly broken, and no cleavage; the image alone cannot confirm the pebble’s exact composition or specific gravity.

Identified September 28, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely a quartz-rich rock hardened by metamorphism, then rounded by transport in water and stained by iron oxides. Its age and original geological setting cannot be determined from appearance alone.

Uses & applications

Primarily a decorative or collectible pebble; quartzite is also used as aggregate, paving, and building stone.

Geological facts

Iron oxides can create brown, ochre, or rusty coloration on otherwise pale quartz-rich rocks.

Field identification & locations

Look for a very hard surface that resists scratching by a steel knife and a granular, interlocking texture on an unpolished break; common in river gravels and glacial deposits. A fresh fracture or simple hardness test would help distinguish quartzite from other brown pebbles.