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These strange and handsome Geodes are from the Henry Mountains of Utah. Originally formed in an ancient sea floor some 50-70 million years ago, sediment collected around sea life as they decomposed, forming a concretion. Calcium carbonate from the shells of these creatures began to take a new form over time, creating calcite crystals and bands of aragonite. As the oceans receded, these mud balls hardened, shrinking and cracking in the sun. The gold-colored crystals inside are the calcite, the brown is aragonite, and the outer surface is composed of limestone.