gemstone

Polished blue chalcedony or glass-like quartz specimen

Chalcedony (microcrystalline SiO₂), possibly treated or synthetic; exact identification requires testing

AI-generated identification · may be incorrect

Translucent pale blue with a vitreous-to-waxy luster and rounded polished form; quartz hardness is about 7 Mohs, no visible cleavage, and specific gravity near 2.6. The smooth dome and strong translucency may also indicate a polished cabochon or treated material.

Identified August 9, 2026More gemstone →

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At a glance

Common name: Polished blue chalcedony or glass-like quartz specimen
Scientific name: Chalcedony (microcrystalline SiO₂), possibly treated or synthetic; exact identification requires testing
Category: gemstone
Identified: August 9, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small common polished piece; $30–$150+ for attractive natural blue chalcedony, depending on color, clarity, provenance, and treatment.

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 chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks, over long periods from the Precambrian to the present. Blue color can result from fine inclusions or treatments.

Uses & applications

Used for cabochons, jewelry, carvings, and decorative objects; ordinary pieces have modest value.

Geological facts

Chalcedony is cryptocrystalline quartz composed of intergrown quartz and moganite. A refractometer, hardness test, magnification, and specific-gravity measurement can distinguish it from glass or resin.

Field identification & locations

Common sources include Brazil, Uruguay, India, Madagascar, Namibia, and the United States. Check for bubbles, flow lines, or unusually low hardness, which suggest glass or plastic; natural chalcedony commonly shows cloudy internal texture.