Clear calcite crystals completely fill and adorn this geode from the Hamilton, Illinois area. It was collected from a geode bearing outcrop just outside of town. It formed on an ancient sea floor some 350 million years ago during the Mississippian Period. This ancient environment now lays exposed in portions of Missouri, Iowa, and Illinois in an area known as the Keokuk Region, which boasts some of the world's best geodes.
It is composed of an outer shell of chalcedony that has been filled with calcite crystals. There is also a tiny ferroan dolomite crystal cluster nestled in the midst of the calcite. The calcite crystals are well formed and have excellent luster and shine. The dolomite and calcite compliment each other nicely making this geode very aesthetically appealing.Item #631