🪨 Geode facts
| Age | Early Cretaceous, about 130–135 million years old (Paraná–Etendeka basalts) |
|---|---|
| Origin & sources | Artigas Department, Uruguay and the neighboring Rio Grande do Sul, Brazil. |
| Composition | Deep-purple amethyst lining a chalcedony rind, often with calcite and goethite inclusions |
How it forms
Huge gas cavities in the thick basalt flows that erupted as South America and Africa split apart later filled with silica-rich hydrothermal fluids, growing dark amethyst. Tall examples are sold as 'cathedrals'.
Mineral data: see Amethyst.
🌍 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
Purple
Third EyeCrown
Healing crystal




