metamorphic

Polished greenstone (likely serpentine or nephrite-like material)

Serpentine-group minerals, commonly antigorite/lizardite; possible nephrite (actinolite–tremolite amphibole)

AI-generated identification · may be incorrect

Dark olive-green, mottled and weakly translucent with a waxy to dull luster; likely Mohs 3–6, with no obvious cleavage and a fine-grained compact texture. The rounded, polished surface makes exact identification uncertain.

Identified August 15, 2026More metamorphic →

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At a glance

Common name: Polished greenstone (likely serpentine or nephrite-like material)
Scientific name: Serpentine-group minerals, commonly antigorite/lizardite; possible nephrite (actinolite–tremolite amphibole)
Category: metamorphic
Identified: August 15, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common polished piece; $50–$500+ if confirmed as high-quality nephrite.

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

Serpentine forms when ultramafic mantle rocks undergo hydration and alteration, commonly during oceanic or tectonic processes; nephrite forms by metamorphic alteration involving magnesium-rich rocks. Ages vary widely by locality, from Precambrian to recent tectonic settings.

Uses & applications

Used for carvings, cabochons, beads, ornamental objects, and occasionally architectural stone; nephrite-quality material can be valuable, while ordinary serpentine is inexpensive.

Geological facts

Greenstone is a broad trade term rather than a single mineral. Serpentine is generally softer and lighter than nephrite and may show a greasy or waxy feel.

Field identification & locations

Look for mottled olive coloration, compactness, and waxy luster; hardness and specific-gravity tests, plus microscopy or Raman/XRF analysis, are needed to distinguish serpentine from nephrite. Common sources include New Zealand, China, Canada, Russia, Italy, and the United States.