Geode

Geodesgeological formations commonIndiana,Keokuk areaIowa, Kentucky, BrazilMexico. Essentially rock bubblesinternal cystal formations,exterior ofgeodegenerally limestone orrelated rock, whileinterior contains quartz crystals and/or chalcedony deposits. Geodes work their way up tosurface ofearth crust's after millionsyears. Geologists do not yet havewidely accepted theory about how geodesformed.