metamorphic

Greenstone (likely altered basalt or serpentinite)

Chlorite–epidote amphibolite/greenschist or serpentinite; exact identification requires testing

AI-generated identification · may be incorrect

Small, irregular, olive-green to brown specimen with dull to slightly waxy luster and probable fine-grained texture. Estimated Mohs hardness 3–6 depending on composition; no obvious cleavage or visible crystals.

Identified September 16, 2026More metamorphic →

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At a glance

Common name: Greenstone (likely altered basalt or serpentinite)
Scientific name: Chlorite–epidote amphibolite/greenschist or serpentinite; exact identification requires testing
Category: metamorphic
Identified: September 16, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a common rough fragment; higher only if provenance, unusual mineralogy, or lapidary quality is established.

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

Likely formed by low- to medium-grade metamorphism or hydrothermal alteration of mafic volcanic rock, possibly during Precambrian to Phanerozoic tectonic activity. Serpentinite, if confirmed, formed by hydration of peridotite in oceanic or subduction-zone settings.

Uses & applications

Greenstone is used decoratively, as lapidary material, and occasionally for carvings or landscaping; serpentinite is also used as ornamental stone. This small rough piece has minimal commercial value.

Geological facts

The term “greenstone” is descriptive rather than a single mineral or rock species. Green color commonly comes from chlorite, epidote, actinolite, or serpentine minerals.

Field identification & locations

Common in metamorphic belts and former oceanic crust; notable sources include the Alps, Appalachians, New Zealand, California, and many Precambrian shields. Check streak, hardness, magnetism, acid reaction, and fibrous texture; a laboratory or thin-section test is needed for confident identification.