metamorphic

Banded river pebble, likely gneiss

Foliated quartz–feldspar rock, possibly banded gneiss

AI-generated identification · may be incorrect

Rounded, smooth pebble with dark gray and tan wavy bands. Likely composed mainly of quartz and feldspar with dark mica or other mafic minerals; exact hardness and mineral makeup cannot be confirmed from the photo (gneiss is typically 6–7 Mohs).

Identified September 27, 2026More metamorphic →

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Physical properties

Formation & geological history

If gneiss, it formed when pre-existing rock was recrystallized and banded under high heat and pressure, often deep in continental crust; its age is unknown. The rounded shape indicates prolonged wear in water or sediment.

Uses & applications

Primarily a natural keepsake or collecting specimen; gneiss is also used as dimension stone and aggregate.

Geological facts

The visible bands resemble gneissic foliation, but pebble weathering and lighting can obscure the texture needed for a confident rock identification.

Field identification & locations

Look for alternating light quartz/feldspar-rich and dark mineral-rich bands that continue through a freshly broken surface. Banded pebbles occur in river and beach gravels derived from metamorphic terrain.