gemstone

Iridescent polished gemstone, likely opal

Common or precious opal (hydrated amorphous silica, SiO₂·nH₂O), possibly synthetic or glass imitation

AI-generated identification · may be incorrect

Small polished oval with green-blue play-of-color and yellow-green body; vitreous to waxy luster, no visible cleavage, amorphous structure, Mohs hardness about 5.5–6.5, specific gravity 1.98–2.25. The unusually vivid, sharply separated colors make synthetic opal or an imitation possible.

Identified August 15, 2026More gemstone →

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At a glance

Common name: Iridescent polished gemstone, likely opal
Scientific name: Common or precious opal (hydrated amorphous silica, SiO₂·nH₂O), possibly synthetic or glass imitation
Category: gemstone
Identified: August 15, 2026
Method: Standard

AI Estimated Value

Approximately $1–$20 if synthetic or imitation; $20–$200+ if confirmed natural and attractive, with exceptional opal worth far more.

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

Natural opal forms when silica-rich groundwater deposits hydrated silica in cavities and fractures, commonly in volcanic or sedimentary settings; deposits range from Cretaceous to recent. Synthetic opal is manufactured by arranging silica spheres.

Uses & applications

Used in jewelry and cabochons; natural fine opal can be valuable, while synthetic pieces are decorative and inexpensive.

Geological facts

Play-of-color results from diffraction by regularly spaced silica spheres, not ordinary surface pigmentation.

Field identification & locations

Check with a loupe for a natural irregular color pattern, visible layers, bubbles, or a plastic-like appearance; hardness, UV response, and specific gravity testing can help, but laboratory testing is definitive. Common sources include Australia, Ethiopia, Mexico, and Nevada.