4 inch Septarian Nodule Stone Sphere Decorator Rock
A pretty, hand cut, not quite 4 inches in diameter, beautiful Septarian Nodule sphere from Utah.
This material was formed when the Gulf of Mexico extended into what is now Southern Utah.
Decomposing sea life (especially seashells) had molecular attraction for the sediment surrounding them, forming mud balls. As the ocean receded, the balls dried and cracked. The oceans returned, depositing more sediments.
Aragonite then formed on the edges of the cracks and yellow Calcite crystals formed in the spaces. The name comes from the Aragonite dividing ("septurn" in Latin) the calcite from the clay.
This wonderful sphere has several small vugs of yellow crystals. And one small opening were the mud popped out (first picture).