Septarian (aka Dragonstone) Polished Nodule

This lovely large palm-sized galet contains a fossil (see photo). Septarian is a unique mix of rock, mineral and organic matter. It is often formed within and carved from layers of limestone sediment. The formation requires a chemical reaction of moistening and drying effects wherever nodules have the chance to seal out of the pockets of empty space in between. Septarian nodules—or as they are technically named “concretions”—are the result of volcanic activity when mud and organic matter are trapped to be sealed by pressure and desiccation (intense drying) in a cemented state, hence the use of the derivative of “concrete.” What makes a Septarian concretion so special is the addition of organic matter added into the mix. Septarian nodules formed as a result of volcanic eruptions and compressed matter of Dead Sea creatures. Septarian nodules originate from the Cretaceous period and formed anywhere between 50 to 70 million years ago. Common minerals found within: Yellow Calcite, Brown Aragonite, Gray Limestone, White Barite. Size: ~3x2" Weight: >3/4 lb Origin: Mahajanga, Madagascar circa 2004 Fairly traded direct from Madagascar, supporting small family business.