925 Silver Hallmarked Michigan Septarian Bangle. Septarian or Lightning Stone is a concretion of hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes also occur. The word 'concretion' is derived from the Latin con meaning 'together' and crescere meaning 'to grow'. Concretions form within layers of sedimentary strata that have already been deposited. They usually form early in the burial history of the sediment, before the rest of the sediment is hardened into rock. This concretionary cement often makes the concretion harder and more resistant to weathering than the host stratum. * Septarian nurtures and grounds the wearer, bringing about feelings of happiness and understanding. This versatile stone is also a speaking stone that is said to improve communication skills of the holder. Septarian is associated with the lower chakras: root, sacral and solar plexus.