metamorphic

Greenstone (likely serpentinite or altered basalt)

Serpentinite, predominantly serpentine-group minerals (Mg₃Si₂O₅(OH)₄); possibly chlorite- or actinolite-rich greenschist

AI-generated identification · may be incorrect

Dark olive-green, fine-grained, dull to slightly waxy luster, massive texture, and no obvious crystal faces or cleavage. Typical hardness is Mohs 2.5–4; exact identification requires hardness, streak, magnetism, and specific-gravity tests.

Identified September 11, 2026More metamorphic →

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At a glance

Common name: Greenstone (likely serpentinite or altered basalt)
Scientific name: Serpentinite, predominantly serpentine-group minerals (Mg₃Si₂O₅(OH)₄); possibly chlorite- or actinolite-rich greenschist
Category: metamorphic
Identified: September 11, 2026
Method: Standard

AI Estimated Value

About $5–$25 for a common hand specimen; $30–$100+ if polished, vividly patterned, or well documented.

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

Most likely formed by low- to moderate-temperature metamorphic alteration of ultramafic rock or basalt during hydration and tectonic activity. Such rocks range from Precambrian to modern plate-boundary settings.

Uses & applications

Commonly used as decorative stone, carvings, beads, and occasionally architectural facing; specimen value is usually modest unless it has attractive veining or unusual texture.

Geological facts

“Greenstone” is a broad field term rather than one mineral species; visually similar rocks include serpentinite, greenschist, chlorite schist, and altered basalt.

Field identification & locations

Look for a green color, fine granular texture, and waxy feel; serpentinite may show pale veins and can produce a white streak. Common localities include California, Italy, New Zealand, Canada, and oceanic suture zones.