Septarian shields are a formation where brown aragonite has formed into a concretion or nodule*, then cracked as it dried out over time. The cracks were then filled in with a solution of calcium carbonate, which hardened into a white-to-yellow mineral. When these nodules — a type of geode — are cracked open, we can see the two minerals have formed a fascinating pattern. No two pieces are the same. The name “septarian” comes from the Latin word for the number seven, because seven is a common number of main divisions to find in the geode. This formation is also called a Thunder Egg.
Properties: Use at the 1st Chakra (Root Chakra/Base Chakra) or at the 2nd Chakra (Sacral Chakra/Spleenic Chakra) to promote bravery and courage, to calm fiery attitudes (anger, frustration, etc.), for grounding, to connect one with the energies of the fire element, to aid one in learning the importance self-control, to stabilize the emotional body, to aid in transformation (physical, emotional, and spiritual), and to help someone to become well-rounded. This stone contains Golden Calcite and Brown Aragonite, so these properties also apply.
Lore: Septarian shields are great for peaceful contemplation, but they originated from processes that were not peaceful at all. Way back in the time of the dinosaurs, when water covered a large part of what is now America, volcanic eruptions killed large numbers of tiny sea animals. After their shells sank to the bottom of the sea, mud balls formed around them. Later, when the seas dried up, the mud balls were left high and dry, and they cracked. But as they say, nature abhors a vacuum; in time, mineral-rich water filled in the cracks with chalky guck. The pretty patterns we see in the geodes we call septarian shields come from the conglomeration of all these sources: whitish calcite from in the center, brown aragonite from the shells, and grey limestone from those primeval mud balls. When you crack one open, you’re seeing a piece of the earth’s history.
* Note: There’s a technical geological difference between concretions and nodules, but the septarian shields are commonly called both concretions and nodules.