metamorphic

Serpentinite (serpentine-rich metamorphic rock)

Serpentine-group minerals, chiefly antigorite, lizardite, and chrysotile; commonly with magnetite and minor brucite

AI-generated identification · may be incorrect

Typically dark green to black, mottled or veined, with waxy to dull luster and fine-grained massive texture; Mohs hardness about 2.5–5.5, no obvious cleavage, and specific gravity around 2.5–2.6. The specimen’s folded green-black banding is consistent with serpentinite, though a photo cannot confirm the identification.

Identified September 1, 2026More metamorphic →

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At a glance

Common name: Serpentinite (serpentine-rich metamorphic rock)
Scientific name: Serpentine-group minerals, chiefly antigorite, lizardite, and chrysotile; commonly with magnetite and minor brucite
Category: metamorphic
Identified: September 1, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$150 for distinctive, polished, or display-quality 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 seafloor alteration or subduction; most examples are Paleozoic to Mesozoic or younger, depending on the tectonic belt. It commonly occurs in ophiolites and fault zones.

Uses & applications

Used as decorative stone, carving material, countertops, and historically as a source of asbestos-bearing material; fibrous varieties should not be cut or abraded because of inhalation hazards. Attractive polished pieces are collected as ornamental stone.

Geological facts

Often contains magnetite, making it unusually dense and sometimes weakly magnetic. Its green color and slick, waxy appearance reflect hydration of olivine- and pyroxene-rich rocks.

Field identification & locations

Look for green-black color, waxy surface, slickensides, veining, and possible magnetism; common localities include California, Italy, New Zealand, Canada, and the Alps. Avoid testing by generating dust, especially if chrysotile is present.