metamorphic

Serpentinite (serpentine-rich rock)

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

AI-generated identification · may be incorrect

Pale green, mottled and waxy to dull luster, massive rather than visibly crystalline; typically Mohs hardness 2.5–4, poor cleavage, and specific gravity about 2.5–2.6. The rusty brown patches likely represent iron oxidation or minor magnetite.

Identified August 20, 2026More metamorphic →

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At a glance

Common name: Serpentinite (serpentine-rich rock)
Scientific name: Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, brucite, and talc
Category: metamorphic
Identified: August 20, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$150+ for polished, patterned, or historically notable material.

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 by low-temperature hydrothermal fluids, commonly in oceanic crust and tectonic suture zones. Individual specimens may be Paleozoic to modern in age, depending on the host terrane.

Uses & applications

Used as decorative stone, carvings, countertops, and historically as a source of magnesium; attractive varieties are collected, though asbestos-bearing forms require caution when cutting or sanding.

Geological facts

Often displays a characteristic green ‘scaly’ or mottled appearance and may feel unusually soft and smooth. Some serpentinite contains chrysotile or other fibrous asbestos minerals.

Field identification & locations

Common in California, the Appalachians, the Alps, New Zealand, and ophiolite belts worldwide. Identify by its green color, waxy surface, softness, and association with dark ultramafic rocks; exact identification requires testing or microscopy.