metamorphic

Greenstone (likely serpentinite or greenstone pebble)

Serpentinite-rich ultramafic rock; commonly dominated by serpentine-group minerals, with possible chlorite, actinolite, or magnetite

AI-generated identification · may be incorrect

Fine-grained, rounded and polished naturally; mottled gray-green color with dull to waxy luster. Typical hardness is about 2.5–5.5 Mohs, with no visible cleavage and variable specific gravity around 2.5–2.8.

Identified August 12, 2026More metamorphic →

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At a glance

Common name: Greenstone (likely serpentinite or greenstone pebble)
Scientific name: Serpentinite-rich ultramafic rock; commonly dominated by serpentine-group minerals, with possible chlorite, actinolite, or magnetite
Category: metamorphic
Identified: August 12, 2026
Method: Standard

AI Estimated Value

Approximately $3–$15 for a common pebble; $20–$75 for attractive polished or unusually patterned specimens.

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

Likely formed by hydration and low-temperature metamorphism of mantle-derived peridotite, commonly in oceanic crust or tectonic suture zones. Serpentinite ranges from ancient Precambrian to geologically recent formations.

Uses & applications

Used as decorative stone, carvings, tumbled specimens, aggregate, and occasionally architectural stone; attractive pieces have modest lapidary value.

Geological facts

The green color commonly comes from serpentine minerals and iron-bearing alteration products. Magnetite may make some specimens weakly magnetic.

Field identification & locations

Identify by its green mottling, soft-to-medium hardness, waxy feel, and tendency to scratch with steel; vinegar produces no reaction. Common sources include California, Italy, New Zealand, Canada, and Japan.