metamorphic

Green Slate Pebble (Serpentine / Greenschist Pebble)

Greenschist / Low-grade Metamorphic Rock

AI-generated identification · may be incorrect

Hardness: 3-5 on Mohs scale; Color: muted greenish-grey with subtle banding; Luster: dull to faintly waxy; Structure: fine-grained, slightly foliated; Cleavage: good basal/slaty cleavage tendencies.

Hardness: 3-5 on Mohs scale
Color: muted greenish-grey with subtle banding
Luster: dull to faintly waxy

Identified July 25, 2026More metamorphic →

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Physical properties

Hardness: 3-5 on Mohs scale; Color: muted greenish-grey with subtle banding; Luster: dull to faintly waxy; Structure: fine-grained, slightly foliated; Cleavage: good basal/slaty cleavage tendencies.

Formation & geological history

Formed through low-grade regional metamorphism of basalt, gabbro, or muddy sedimentary rocks containing chlorite, epidote, or actinolite under low-to-moderate temperature and pressure conditions, later water-worn into a smooth river/beach pebble.

Uses & applications

Commonly collected as a beach pebble or used in decorative landscaping, rock gardens, and tumbling projects.

Geological facts

Green-toned metamorphic pebbles owe their distinct olive to blue-green hues primarily to the presence of chlorite minerals formed during metamorphism. They are frequently smoothed naturally by river currents or ocean waves.

Field identification & locations

Identify in the field by its smooth, water-worn elongated shape, soft green-grey tint, fine grain, and moderate hardness. Commonly found along stream beds, riverbanks, and coastal gravel beaches worldwide.