metamorphic

Veined dark metamorphic rock, likely serpentinite

Serpentinite, predominantly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible quartz, calcite, and magnetite veins

AI-generated identification · may be incorrect

Typically dark green-black to gray, waxy or greasy luster, fine-grained massive texture, Mohs hardness about 2.5–4, and density around 2.5–2.7. The pale branching veins may be calcite or quartz; the image alone cannot confirm the exact mineralogy.

Identified September 6, 2026More metamorphic →

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At a glance

Common name: Veined dark metamorphic rock, likely serpentinite
Scientific name: Serpentinite, predominantly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible quartz, calcite, and magnetite veins
Category: metamorphic
Identified: September 6, 2026
Method: Standard

AI Estimated Value

$5–$30 for a common hand specimen; approximately $30–$150 for unusually attractive polished or strongly veined 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 hydrothermal alteration, commonly along oceanic crust and tectonic fault zones. Most examples are Paleozoic to Mesozoic or younger, depending on the terrane.

Uses & applications

Used as decorative facing stone, carvings, aggregate, and historically as a source rock associated with asbestos minerals; attractive pieces are collected but are generally not jewelry-grade.

Geological facts

Serpentinite commonly displays slickensides, veining, and mottled green-black coloration. Avoid cutting, sanding, or crushing unknown specimens because some serpentinites contain fibrous asbestos minerals.

Field identification & locations

Field clues include unusually dark green-black color, waxy feel, low hardness, and pale veins; a steel knife may scratch it, while quartz veins resist scratching. Common in ophiolites and subduction-zone mélanges.