mineral

Tumbled pale-green stone, likely prehnite or serpentine

Most consistent with massive prehnite, Ca₂Al₂Si₃O₁₀(OH)₂; serpentine is a possible alternative

AI-generated identification · may be incorrect

Pale blue-green, opaque to translucent, waxy-to-dull luster, rounded and polished; hardness approximately Mohs 6–6.5 for prehnite (serpentine 2.5–5.5), with no obvious cleavage. Exact identification requires hardness, streak, and possibly chemical or microscopic testing.

Identified August 13, 2026More mineral →

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At a glance

Common name: Tumbled pale-green stone, likely prehnite or serpentine
Scientific name: Most consistent with massive prehnite, Ca₂Al₂Si₃O₁₀(OH)₂; serpentine is a possible alternative
Category: mineral
Identified: August 13, 2026
Method: Standard

AI Estimated Value

About $1–$10 as a common tumbled stone; attractive translucent prehnite pieces may sell for $10–$40.

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

Prehnite commonly forms as a secondary mineral in cavities and fractures of basalt and other volcanic rocks, generally in relatively young hydrothermal systems; serpentine forms by alteration of ultramafic rocks. The image alone cannot establish geological age.

Uses & applications

Used as a lapidary stone, carving material, and inexpensive cabochon or tumbled stone; massive material has little industrial use.

Geological facts

The rounded shape and uniform surface indicate human tumbling or water wear rather than a crystal specimen. Prehnite may show botryoidal forms and subtle pearly translucence, while serpentine is typically softer and more waxy.

Field identification & locations

Look for pale green color, translucence at thin edges, and hardness sufficient to scratch glass for prehnite; a steel nail may scratch serpentine but usually not prehnite. Common sources include Australia, South Africa, India, China, and the United States.