sedimentary

Geode / Fossilized Gastropod or Shell Cast

Silicon dioxide (Quartz) replacement / fossil mold

AI-generated identification · may be incorrect

Hardness of 7 (for the quartz lining), earthy to vitreous luster, amorphous to cryptocrystalline exterior with microcrystalline quartz crystals lining the inner cavity, conchoidal fracture.

Identified July 28, 2026More sedimentary →

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Physical properties

Hardness of 7 (for the quartz lining), earthy to vitreous luster, amorphous to cryptocrystalline exterior with microcrystalline quartz crystals lining the inner cavity, conchoidal fracture.

Formation & geological history

Formed in sedimentary environments where shells or cavities in rock are slowly dissolved and replaced by mineral-rich groundwater precipitating silica over millions of years.

Uses & applications

Collectible specimen, lapidary arts, metaphysical uses, and educational displays.

Geological facts

Fossilized shells and hollow nodules often act as natural traps for mineral precipitation, resulting in hollow rocks lined with sparkling quartz or chalcedony crystals.

Field identification & locations

Identify by its hollow interior, crystal-lined cavity, and external weathered sedimentary crust. Often found in limestone formations, riverbeds, and desert regions worldwide.