mineral
Chalcedony Geode
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, grayish-blue color, vitreous to waxy luster, microcrystalline crystal structure, conchoidal fracture with no true cleavage, specific gravity of 2.60 to 2.65.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, grayish-blue color, vitreous to waxy luster, microcrystalline crystal structure, conchoidal fracture with no true cleavage, specific gravity of 2.60 to 2.65.
Formation & geological history
Formed when mineral-rich groundwater or hydrothermal fluids deposit silica in hollow cavities of sedimentary or volcanic rocks over millions of years.
Uses & applications
Used in ornamental carvings, gemstone jewelry, lapidary art, and cherished by mineral collectors.
Geological facts
Geodes start as bubbles in volcanic rock or animal burrows in sedimentary rock, slowly filling inward with microscopic quartz crystals to form a hollow center lined with crystals.
Field identification & locations
Easily identified by its nodular exterior and hollow center lined with microcrystalline quartz or chalcedony. Commonly found globally in volcanic regions such as Brazil, Mexico, and the western United States.
