mineral
Blue chalcedony (likely dyed or coated)
Microcrystalline quartz, SiO₂ (chalcedony)
AI-generated identification · may be incorrectPale blue, translucent, waxy-to-glassy luster, and no visible cleavage; quartz hardness is Mohs 6.5–7 and specific gravity about 2.6. The smooth, irregular shape and unusually vivid color suggest a polished/tumbled piece, possibly dyed or resin-coated.
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Physical properties
Pale blue, translucent, waxy-to-glassy luster, and no visible cleavage; quartz hardness is Mohs 6.5–7 and specific gravity about 2.6. The smooth, irregular shape and unusually vivid color suggest a polished/tumbled piece, possibly dyed or resin-coated.
Formation & geological history
Natural chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; formation ages vary widely, from recent deposits to Paleozoic and older. Blue color may be natural from inclusions or enhanced artificially.
Uses & applications
Used for cabochons, beads, carvings, ornamental objects, and mineral collections; it is not generally used as a construction stone. Value is primarily aesthetic and depends on color, translucency, treatment, and size.
Geological facts
Chalcedony is a variety of cryptocrystalline quartz composed of intergrown quartz and moganite. A glass-scratch test or quartz hardness comparison can help, but laboratory testing is needed to confirm treatment.
Field identification & locations
Common sources include Namibia, Turkey, Indonesia, Brazil, Madagascar, and the western United States. Identify it by its waxy appearance, translucency, conchoidal fracture, and lack of cleavage; vivid uniform blue often indicates dyeing.
