metamorphic

Banded river pebble (likely greenstone)

Likely chlorite- and amphibole-rich greenstone; exact identification requires testing

AI-generated identification · may be incorrect

Smooth, rounded, dark olive-green pebble with pale bands and a dull to slight sheen. Likely Mohs 5–6; fine-grained, with no visible crystals or cleavage.

Identified October 11, 2026More metamorphic →

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Physical properties

Smooth, rounded, dark olive-green pebble with pale bands and a dull to slight sheen. Likely Mohs 5–6; fine-grained, with no visible crystals or cleavage.

Formation & geological history

Probably a water-worn metamorphic rock, formed when mafic volcanic rock was altered by heat and fluids; its age and precise origin cannot be determined from the image.

Uses & applications

Primarily a keepsake or lapidary material; suitable for tumbling or simple carving if the bands continue through the stone.

Geological facts

Greenstone is a broad field term for altered, green-colored mafic rocks, commonly colored by chlorite, actinolite, or epidote.

Field identification & locations

The rounded shape suggests stream or beach transport. Check a fresh surface and hardness to distinguish greenstone from banded serpentinite or another dark, fine-grained pebble.