Septarian Nodule, also referred to as Dragon Stone, is a tri colour concretion composed of Aragonite (the brown), Calcite, (the yellow), and Limestone (the grey). The name comes from the word “Septaria”, which usually refers to any concretion with internal cavities or cracks. This unique mineral was formed around 50 to 70 million years ago during Earth’s Cretaceous Period. Sea life during that time became attracted to the molten sediment that was produced by these massive volcanic eruptions. Overtime as sea life began to die, their chemical composition became enriched in sedimentary rock, forming the nodules we see today. As oceans began to recede around the world, the water within soon dried out and massive cracks formed internally. The chemicals within the dead sea life eventually crystallized and formed Aragonite “crusts” and drusy Calcite crystals. Most Septarian Nodules are from Utah or Madagascar, which was under very similar conditions during that time period. This rock type has lovely colours and fantastic patterns.
