sedimentary
Agate Geode
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, exhibits concentric banding with a vitreous to dull luster and cryptocrystalline structure. Shows no cleavage and has a specific gravity of roughly 2.65.
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Physical properties
Hardness of 7 on the Mohs scale, exhibits concentric banding with a vitreous to dull luster and cryptocrystalline structure. Shows no cleavage and has a specific gravity of roughly 2.65.
Formation & geological history
Formed via the deposition of silica-rich groundwater solutions within cavities of volcanic or sedimentary rocks over millions of years.
Uses & applications
Widely used in lapidary arts, ornamental carving, gemstone jewelry, and sought after by mineral collectors.
Geological facts
Geodes form when groundwater minerals precipitate inside hollow bubbles within volcanic basalt or ancient limestone nodules. The outer shell hardens while inner cavities grow sparkling quartz crystals.
Field identification & locations
Identify by distinctive concentric banding, conchoidal fracture, and high hardness capable of scratching glass. Commonly found in volcanic regions and riverbeds worldwide.
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