sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
Hardness of 7 on the Mohs scale, predominantly white to clear color, vitreous to sugary luster, hexagonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65
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Physical properties
Hardness of 7 on the Mohs scale, predominantly white to clear color, vitreous to sugary luster, hexagonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65
Formation & geological history
Formed in hollow cavities in sedimentary or volcanic rock where silica-rich groundwater percolated through, slowly depositing microscopic quartz crystals along the inner walls over millions of years.
Uses & applications
Popular among rockhounds and mineral collectors, used for decorative items, metaphysical purposes, and sometimes cut into polished display pieces or jewelry.
Geological facts
Geodes start as empty bubbles or nodules in host rock. Over time, mineral-rich water enters and deposits crystals from the outside inward, eventually creating a hollow center lined with sparkling quartz crystals.
Field identification & locations
Found frequently in limestone formations, basalt flows, and areas with weathered sedimentary layers. Collectors typically identify them by their rounded, nodular exterior texture and sparkling crystal interior when cracked open.
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