gemstone

Polished opal-like chalcedony

Cryptocrystalline silica, SiO₂; likely common opal or pale chalcedony, with identification limited by the photograph

AI-generated identification · may be incorrect

Translucent milky-white to pale yellow, vitreous-to-waxy luster, conchoidal fracture, and no visible cleavage; hardness is approximately 5.5–7 Mohs depending on whether it is opal or chalcedony. The triangular form appears cut and polished rather than naturally crystallized.

Identified August 9, 2026More gemstone →

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At a glance

Common name: Polished opal-like chalcedony
Scientific name: Cryptocrystalline silica, SiO₂; likely common opal or pale chalcedony, with identification limited by the photograph
Category: gemstone
Identified: August 9, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 for a small common-opal or chalcedony piece; $50–$300+ if it proves to be attractive precious opal.

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

Opal forms when silica-rich water deposits hydrated silica gel in cavities and fractures; chalcedony forms from microcrystalline quartz in veins and cavities. These materials are generally young to Phanerozoic, though host-rock ages vary widely.

Uses & applications

Used as a cabochon, carving, ornamental stone, or inexpensive jewelry gem; similar material is also used for small polished collectibles.

Geological facts

Common opal lacks play-of-color, whereas precious opal shows shifting spectral flashes; the image shows translucency but no obvious play-of-color.

Field identification & locations

Look for conchoidal fracture, translucency, waxy luster, and a scratch resistance consistent with silica; a refractometer, specific gravity test, or loupe examination can distinguish opal from chalcedony. Common sources include Australia, Ethiopia, Mexico, Brazil, and the western United States.