metamorphic

Serpentinite (likely)

Serpentinite; predominantly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and relic olivine/pyroxene

AI-generated identification · may be incorrect

Dark green-black, mottled and subtly waxy to greasy luster with yellow-green veins; typically massive and fine-grained, Mohs hardness about 2.5–4, with no obvious cleavage and specific gravity roughly 2.5–2.7. The specimen may also contain harder, metallic-looking sulfides or accessory minerals.

Identified September 2, 2026More metamorphic →

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At a glance

Common name: Serpentinite (likely)
Scientific name: Serpentinite; predominantly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and relic olivine/pyroxene
Category: metamorphic
Identified: September 2, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$150+ for large, polished, strongly veined, or locality-labeled 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 hydrate during low-temperature metamorphism, commonly along oceanic crust and fault zones. Ages range from Precambrian to modern tectonic settings; precise age cannot be determined visually.

Uses & applications

Used as decorative stone, carvings, countertops, and historically as a source of ornamental “verde antique”; collectors value attractive veining and polish. Chrysotile-bearing material should not be cut, drilled, or powdered because its dust can be hazardous.

Geological facts

Serpentinite records interaction between rock and water and can host unusual chromium-, nickel-, and cobalt-rich minerals. Its dark green color and slick-looking surfaces commonly result from serpentine minerals and magnetite.

Field identification & locations

Identify it by its green-black mottling, waxy feel, low hardness, and possible magnetism; a streak, hardness, acid, and thin-section test would help confirm it. Common occurrences include California, Italy, New Zealand, Canada, and many former oceanic-rock belts.