🪨 Geode facts
| Age | Varies; Midwestern US quartz geodes are Mississippian, about 340 million years |
|---|---|
| Origin & sources | USA (Iowa, Missouri, Illinois, Kentucky, Indiana), Mexico, Morocco, Brazil. |
| Composition | Chalcedony or limestone shell lined with clear or milky quartz crystals |
How it forms
Silica-rich water filled hollow nodules or cavities and slowly grew quartz crystals inward from the walls.
Mineral data: see Quartz.
🌍 Where it's found
- Type locality
- Notable source / deposit
- Country of origin
Marker positions are approximate (region or locality level). Type localities from Wikidata; notable sources curated by Crystopedia.
Learn more
Geode / nodule
White & Clear
Crown
Healing crystal



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