Description

Septarian Concreations are commonly composed of a carbonate mineral such as Calcite, a microcrystalline form of Silica as in Flint or Jasper, or an Iron Oxide such as Hematite.  These specimens formed inside of a concretion, a type of sedimentary rock.   Septarian concretions were formed millions of years ago by sediment forming around a fossil to create a mud ball transforming the fossil into Calcite and Aragonite.