Septarian Nodules are concretions that have a series of radiating cracks, crossed by a series of concentric cracks to form a “turtle-back” appearance. They are also known the "Dragon Stone Healing Stone." Ball-like Sepatrian Nodules began their life as sedimentary slime at the bottom of a Cretaceous Sea 50 to 70 million years ago. Sediment composed of decomposing plants and animals formed into balls. Septarians are composed of Limestone, the outer gray rock, Aragonite creating the brown lines. The centers are either yellow (calcite) or black (agate druzy).
Septarian is a "concretion" stone. Concretions are protective stones, providing both grounding and shielding of the physical, mental, and emotional bodies.