metamorphic

Serpentine-rich serpentinite

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible magnetite, brucite, and carbonate

AI-generated identification · may be incorrect

Typically olive-green to brown, mottled, waxy to greasy luster, Mohs hardness about 2.5–4, and massive rather than visibly crystalline; the pale rounded patches may be carbonate or altered silicate minerals. Specific gravity is commonly about 2.5–2.7.

Identified September 21, 2026More metamorphic →

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At a glance

Common name: Serpentine-rich serpentinite
Scientific name: Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible magnetite, brucite, and carbonate
Category: metamorphic
Identified: September 21, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$150 for unusually attractive polished or well-documented examples.

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 undergo hydration and low-temperature metamorphism, commonly in oceanic crust and tectonic fault zones. Most specimens formed during ancient ocean-floor alteration and later uplift; exact age cannot be determined from the image.

Uses & applications

Used as decorative and facing stone, carving material, aggregate, and historically as a source of asbestos-bearing serpentinite; attractive pieces are collected, though fibrous asbestos varieties require caution.

Geological facts

Serpentinite is California’s state rock and commonly records water–rock interaction in former mantle rocks. Its smooth, waxy appearance and green-brown veining are characteristic.

Field identification & locations

Identify it by its low hardness, greasy feel, green mottling, and tendency to scratch with a steel knife; a streak, magnetism test, and asbestos-fiber inspection can help. Common localities include California, Italy, New Zealand, Canada, and the Appalachians.