mineral

Tumbled green stone, likely serpentine or aventurine

Serpentine-group mineral (Mg₃Si₂O₅(OH)₄) or quartz-rich aventurine; exact identification requires testing

AI-generated identification · may be incorrect

Small rounded, polished pebble; olive-green, translucent to opaque, waxy/vitreous luster, no visible crystals or cleavage. Likely hardness Mohs 2.5–4 for serpentine or 6.5–7 for aventurine; specific gravity commonly 2.5–2.7.

Identified August 16, 2026More mineral →

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At a glance

Common name: Tumbled green stone, likely serpentine or aventurine
Scientific name: Serpentine-group mineral (Mg₃Si₂O₅(OH)₄) or quartz-rich aventurine; exact identification requires testing
Category: mineral
Identified: August 16, 2026
Method: Standard

AI Estimated Value

About $1–$5 for a common tumbled pebble; $5–$20 if unusually translucent, patterned, or sold as quality lapidary material.

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 rocks undergo hydration and metamorphism, commonly during tectonic alteration; aventurine forms in silica-rich hydrothermal or metamorphic environments. Ages vary widely by locality.

Uses & applications

Used as a lapidary stone, ornamental pebble, carving material, and inexpensive jewelry component; serpentine is also used decoratively in architecture.

Geological facts

The smooth shape indicates human tumbling rather than natural weathering. A steel knife or glass-scratch test can help distinguish softer serpentine from harder quartz-rich aventurine, but may damage the specimen.

Field identification & locations

Common sources include California, Vermont, Italy, New Zealand, India, Brazil, and Russia. Look for serpentine’s waxy feel and softness versus aventurine’s glassier luster and ability to scratch glass.