metamorphic

Likely altered volcanic rock (greenstone)

Chlorite–epidote–actinolite-rich metavolcanic rock; exact identification requires testing

AI-generated identification · may be incorrect

Dull, mottled green with dark patches and a rough, fine-grained texture. Likely contains chlorite and epidote, possibly amphibole; hardness and mineral proportions cannot be reliably determined from the photo (greenstone is commonly about 5–6 Mohs).

Identified October 8, 2026More metamorphic →

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At a glance

Common name: Likely altered volcanic rock (greenstone)
Scientific name: Chlorite–epidote–actinolite-rich metavolcanic rock; exact identification requires testing
Category: metamorphic
Identified: October 8, 2026
Method: Standard

AI Estimated Value

About $0–$5 for a common hand specimen; higher value would require distinctive minerals, polishability, or verified provenance.

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

Often forms when basaltic volcanic rock is altered by low-grade metamorphism and hydrothermal fluids. The image alone cannot establish its age or precise formation conditions.

Uses & applications

Comparable greenstones are used as aggregate and decorative stone; attractive pieces may be collected, but this fragment shows no obvious gem-quality material.

Geological facts

“Greenstone” is a descriptive field term for green, altered mafic rock, not one single mineral or precisely defined rock type.

Field identification & locations

The green color and granular, uneven surface fit altered volcanic rock, but similar appearances can come from serpentine-rich rocks or copper-bearing material. Chile’s central coast region makes volcanic and metamorphic rocks plausible, though location alone cannot confirm this ID; a fresh-surface inspection and mineral tests would help.