metamorphic

Rounded dark metamorphic pebble

Likely mica schist or chlorite-rich greenschist; exact identification requires testing

AI-generated identification · may be incorrect

Dark gray-green, fine to medium grained, dull to slightly silky luster, and water-worn/rounded. Likely hardness about 3–6 depending on mica and quartz content; cleavage or foliation may be obscured by weathering and abrasion.

Identified August 16, 2026More metamorphic →

Explore Rounded dark metamorphic 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

Probably a river or glacially transported metamorphic fragment, with foliation developed during regional metamorphism. Around 42.9°N, 0.1°W in the Pyrenees, metamorphic rocks are geologically plausible; age may range from Paleozoic to Mesozoic depending on source unit.

Uses & applications

Primarily a natural collecting specimen or decorative pebble; not identifiable as a commercial gemstone from the photograph.

Geological facts

The pale reflective flecks may be mica, while the greenish tone could indicate chlorite. A streak, fresh broken surface, hardness test, and hand lens would distinguish schist from dark volcanic rocks such as basalt.

Field identification & locations

Commonly found in Pyrenean streams and scree derived from metamorphic terranes. Check for visible layered foliation, mica flakes, and a gray-white streak; avoid acid testing unless carbonate veins are suspected.