mineral
Quartz Geode
Silicon Dioxide (SiO2) within a sedimentary/igneous host
Hardness: 7 (Mohs scale), Color: Clear to white crystals within a tan stony outer shell, Luster: Vitreous/glassy crystals, Crystal Structure: Hexagonal (trigonal), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: Clear to white crystals within a tan stony outer shell, Luster: Vitreous/glassy crystals, Crystal Structure: Hexagonal (trigonal), Specific Gravity: 2.65
Formation & geological history
Formed when mineral-rich water seeps into cavities in sedimentary limestone or volcanic ash, leaving layers of crystals that grow inward over millions of years.
Uses & applications
Primarily used for geological education, home decor, metaphysical collecting, and occasionally as a source for small ornamental carvings or lapidary work.
Geological facts
The word geode comes from the Greek word 'Geoides' which means earth-like. No two geodes are exactly alike inside.
Field identification & locations
Identify in the field by looking for round, lumpy rocks that feel lighter than they look (indicating a hollow center). Common locations include Morocco, Mexico, Brazil, and the Midwestern United States.
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