metamorphic

Probable serpentinite (serpentine-rich rock)

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible magnetite and olivine remnants

AI-generated identification · may be incorrect

Dark green-gray, mottled, waxy to slightly greasy luster, irregular fracture, and fine-grained massive texture; Mohs hardness about 2.5–4, with variable density and no consistent cleavage. The small specimen appears rough and naturally fractured, though exact identification requires testing.

Identified August 8, 2026More metamorphic →

Explore Probable serpentinite (serpentine-rich rock) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Probable serpentinite (serpentine-rich rock)
Scientific name: Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible magnetite and olivine remnants
Category: metamorphic
Identified: August 8, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small rough specimen; $30–$150 or more for attractive polished or well-documented 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 along tectonic plate boundaries and fault zones. Serpentinization is generally younger than the original mantle rock and may occur from Precambrian to modern times.

Uses & applications

Used as decorative and architectural stone, carving material, aggregate, and historically as a source of magnesium and asbestos-bearing minerals; attractive pieces are collected.

Geological facts

Often contains magnetite, making some specimens weakly magnetic. Fibrous chrysotile may occur, so avoid grinding or creating dust.

Field identification & locations

Common in ophiolites and ultramafic belts, including California, Italy, New Zealand, and parts of Canada. A waxy green appearance, low hardness, and possible magnetism help distinguish it from ordinary basalt; acid testing is usually ineffective.