mineral

Blue resin-coated or dyed stone cabochon

Likely dyed chalcedony/agate (microcrystalline quartz, SiO₂); exact material is uncertain from the image

AI-generated identification · may be incorrect

Polished round cabochon with vivid turquoise-blue color, translucent cloudy patches, and glassy-to-waxy luster. Quartz-based chalcedony has Mohs hardness 6.5–7, no visible cleavage, cryptocrystalline structure, and specific gravity about 2.6; surface reflections may also indicate a coating.

Identified September 17, 2026More mineral →

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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 Paleozoic to recent geological time; the intense blue color is probably artificial dye or coating. A synthetic glass or resin imitation is also possible.

Uses & applications

Used for inexpensive jewelry, cabochons, ornaments, and decorative objects; commercial value is generally modest unless confirmed as high-quality natural material.

Geological facts

Bright uniform blue is uncommon in untreated chalcedony. Natural quartz should scratch ordinary glass, while dye often concentrates in pores, cracks, or along the rim.

Field identification & locations

Common sources of blue-dyed agate include Brazil, Uruguay, and China. Test inconspicuously for dye transfer with acetone and examine under magnification; hardness and specific-gravity testing can distinguish stone from glass or resin.