metamorphic

Serpentinite (likely)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, brucite, or chromite

AI-generated identification · may be incorrect

Dark green to olive, mottled and waxy to slightly greasy luster; commonly massive with no obvious cleavage. Hardness is typically 2.5–4 Mohs, though included minerals may create brighter metallic flecks; density about 2.5–2.6 g/cm³.

Identified September 3, 2026More metamorphic →

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At a glance

Common name: Serpentinite (likely)
Scientific name: Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, brucite, or chromite
Category: metamorphic
Identified: September 3, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$150 or more for polished, vividly patterned, or unusually large pieces.

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

Forms when ultramafic mantle rocks such as peridotite are hydrated during low-temperature metamorphism, commonly in oceanic lithosphere and tectonic fault zones. Individual specimens may range from ancient Precambrian to geologically young; age cannot be determined visually.

Uses & applications

Used as decorative stone, carvings, countertops, and occasionally as a source or host rock for magnesium, nickel, and chromite. Attractive polished pieces have modest lapidary and collecting value.

Geological facts

Its green color and mottled pattern result from serpentine minerals; magnetite commonly causes dark patches and weak magnetic response. Some varieties contain asbestos-form serpentine, so avoid cutting or generating dust without proper controls.

Field identification & locations

Look for a relatively soft, dense, green-black, waxy stone that may scratch with a steel nail and sometimes feels unusually smooth; identification is provisional from the photograph. Common localities include California, Italy, New Zealand, Canada, and the Appalachians.