mineral
Chalcedony
Silicon dioxide, SiO2
AI-generated identification · may be incorrectMohs hardness of 6.5 to 7. Color varies widely from white to grey, blue, or brown. Luster is waxy to vitreous with a microcrystalline structure and conchoidal fracture.
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Physical properties
Mohs hardness of 6.5 to 7. Color varies widely from white to grey, blue, or brown. Luster is waxy to vitreous with a microcrystalline structure and conchoidal fracture.
Formation & geological history
Forms in low-temperature hydrothermal environments, often depositing within cavities in volcanic or sedimentary rocks from silica-rich solutions.
Uses & applications
Used extensively for ornamental carvings, gemstones, and lapidary art due to its durability and polishability.
Geological facts
Chalcedony is the cryptocrystalline form of silica, serving as the parent material for many popular varieties like agate, jasper, and onyx.
Field identification & locations
Identified by its waxy luster, conchoidal fracture, and lack of visible crystal faces. Commonly found worldwide in volcanic cavities and river gravels.
