metamorphic

Tumbled greenstone or serpentinite pebble

Likely serpentine-group rock (serpentinite); exact identification is uncertain from the image

AI-generated identification · may be incorrect

Smooth, rounded, opaque olive-green surface with a subdued waxy luster. Serpentinite is commonly Mohs 3–5, with fine-grained serpentine minerals and variable composition; the pebble’s hardness and cleavage cannot be determined visually.

Identified October 11, 2026More metamorphic →

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At a glance

Common name: Tumbled greenstone or serpentinite pebble
Scientific name: Likely serpentine-group rock (serpentinite); exact identification is uncertain from the image
Category: metamorphic
Identified: October 11, 2026
Method: Standard

AI Estimated Value

About $1–$10 for an ordinary tumbled pebble; higher prices require confirmed identity, attractive patterning, or larger size.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Serpentinite forms when water alters ultramafic rocks, commonly in oceanic crust and tectonic zones; its age depends on the source rock and alteration. The rounded shape suggests natural water wear or deliberate tumbling.

Uses & applications

Small polished pebbles are used for collecting, crafts, and decorative items; larger serpentinite deposits may be used as ornamental stone.

Geological facts

Serpentine is a group of minerals, not a single mineral species; similar-looking green pebbles can also be greenstone, jade, or other rocks.

Field identification & locations

Look for a fine-grained green interior, waxy feel, and relatively low hardness; definitive identification may require hardness, density, or mineral tests. Serpentinite occurs in many mountain belts and ophiolite complexes.