mineral
Chalcedony
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline structure, and conchoidal fracture. Displays translucent to opaque gray-blue coloration.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline structure, and conchoidal fracture. Displays translucent to opaque gray-blue coloration.
Formation & geological history
Forms in low-temperature hydrothermal environments and by deposition from silica-rich groundwater within cavities of volcanic or sedimentary rocks.
Uses & applications
Commonly used for ornamental carvings, polished gemstones, lapidary art, and geological collecting.
Geological facts
Chalcedony is a cryptocrystalline form of silica, meaning its crystals are too small to be seen without high magnification. Many famous gem varieties like agate, jasper, and onyx are forms of chalcedony.
Field identification & locations
Identified by its waxy luster, conchoidal fracture, and lack of visible crystal faces. Found worldwide in volcanic regions, riverbeds, and nodular deposits.
