gemstone

Blue glassy gemstone cabochon, likely dyed chalcedony or glass

Uncertain; possible dyed chalcedony (microcrystalline quartz, SiO₂)

AI-generated identification · may be incorrect

Small, polished, domed blue cabochon with vitreous luster and apparent translucency. If chalcedony, hardness is about 6.5–7 Mohs, trigonal quartz structure, no cleavage, and specific gravity about 2.6; the photo cannot exclude man-made glass.

Identified September 21, 2026More gemstone →

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Physical properties

Formation & geological history

Chalcedony forms from silica-rich groundwater filling cavities and fractures, commonly in volcanic rocks; its age varies widely. Strong uniform blue color often indicates dye treatment, while glass would be entirely artificial.

Uses & applications

Used in inexpensive jewelry, cabochons, craft items, and collections; natural blue chalcedony is more desirable than dyed material.

Geological facts

Natural blue chalcedony is uncommon; vivid saturated blue specimens are frequently dyed. A rounded polished form indicates human processing.

Field identification & locations

Check with a loupe for dye concentration in cracks, bubbles, or flow lines; test hardness only on an inconspicuous area, and use refractive index or lab testing for confirmation. Common sources include Brazil, India, Madagascar, and Turkey.