mineral
Blue chalcedony (polished cabochon)
Microcrystalline quartz, SiO₂; chalcedony variety
AI-generated identification · may be incorrectMohs hardness 6.5–7; blue-gray, translucent to opaque, with a waxy to vitreous luster and no visible crystal faces. It is a polished, rounded cabochon; specific gravity is about 2.6.
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Physical properties
Mohs hardness 6.5–7; blue-gray, translucent to opaque, with a waxy to vitreous luster and no visible crystal faces. It is a polished, rounded cabochon; specific gravity is about 2.6.
Formation & geological history
Silica-rich fluids deposited microscopic quartz in rock cavities and fractures, commonly in volcanic rocks. Chalcedony forms across many geological ages; the photo does not establish a precise variety or age.
Uses & applications
Used for cabochons, beads, carvings, and ornamental objects; chalcedony is also used in some industrial silica applications.
Geological facts
Chalcedony is quartz with crystals too small to distinguish readily without magnification.
Field identification & locations
Look for a smooth, waxy surface and uniform fine-grained texture; blue chalcedony occurs in several regions, including Turkey, Namibia, and the western United States. The small polished specimen cannot be reliably sourced from appearance alone.
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