metamorphic

Serpentine (likely serpentinite)

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and chromite

AI-generated identification · may be incorrect

Dark green to black, mottled and often waxy or greasy luster; typically massive with fibrous or scaly texture and no obvious cleavage. Hardness is about 2.5–4 Mohs, with variable density; the specimen’s polished-looking green-black pattern is consistent with serpentine.

Identified August 11, 2026More metamorphic →

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At a glance

Common name: Serpentine (likely serpentinite)
Scientific name: Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and chromite
Category: metamorphic
Identified: August 11, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$150 for attractive polished or unusual collector 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 undergo hydration and low-temperature metamorphism, commonly along oceanic crust and tectonic fault zones. Serpentinite ranges from ancient Precambrian bodies to young active plate-boundary occurrences.

Uses & applications

Used as decorative stone, carvings, countertops, and ornamental objects; historically used as a low-grade asbestos source where chrysotile is present. Attractive polished material has modest lapidary and collecting value.

Geological facts

Serpentinite may contain magnetite, giving it a dark appearance and occasional magnetic response. Chrysotile-bearing pieces should not be cut, drilled, or abraded because inhaled fibers are hazardous.

Field identification & locations

Common in ophiolites and subduction-related belts, including California, Oregon, Italy, New Zealand, and the Himalaya. Identify by its green-black waxy appearance, softness, streaking, and reaction to a steel point; confirmation requires microscopy or chemical testing.