mineral
Tumbled blue glass-like specimen, possibly dyed chalcedony or synthetic glass
Uncertain; possible dyed quartz/chalcedony (SiO₂), but appearance strongly suggests cobalt-blue glass
AI-generated identification · may be incorrectDeep translucent cobalt-blue, vitreous luster, rounded/tumbled form, and apparent internal bubbles or flow lines. If quartz, hardness is about 7 Mohs; glass is typically 5–6, with no cleavage.
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Physical properties
Deep translucent cobalt-blue, vitreous luster, rounded/tumbled form, and apparent internal bubbles or flow lines. If quartz, hardness is about 7 Mohs; glass is typically 5–6, with no cleavage.
Formation & geological history
Natural blue chalcedony is uncommon and usually pale blue; vivid cobalt coloration is commonly produced by dyeing quartz or manufacturing glass. The specimen’s geological age cannot be determined from the image.
Uses & applications
Dyed chalcedony may be used for inexpensive ornaments and cabochons; cobalt glass is decorative. Likely limited construction or jewelry value unless confirmed as natural gemstone.
Geological facts
A sharp edge or conchoidal fracture, abundant round bubbles, and flow textures would favor glass. Quartz should scratch ordinary glass, whereas glass generally will not scratch quartz.
Field identification & locations
Check for bubbles, uniform color concentration in cracks, and an indistinct glassy fracture; test hardness cautiously and inspect with magnification. Natural blue quartz/chalcedony typically shows more variable color and mineral texture.
