Septarian Nodules or Concretions
The name 'septarian' comes from the Latin 'septum' meaning a dividing partition between tissues or cavities. This is a fairly accurate description of what it is. In anatomy 'septum' is the cartilage in our nose that divides one nostril from the other.
Although often described as a mineral septarian is a rock. It's more correctly known as a septarian nodule or concretion.
It's made up primarily of calcite, aragonite and limestone.
These nodules formed around the time dinosaurs disappeared and are sometimes described as a kind of prehistoric mud ball. They formed in water over millions of years and geologists now have a pretty good idea about how they evolved.
Each septarian sphere is on a hematite ring which is not included but may be purchased separately. These rings are ideal for supporting spheres of most sizes. Hematite is brittle so will chip or shatter quite easily.
Although well polished it's not unusual for septarian to have minor indentations or anomalies.
