6.4" Beautiful, Crystal Filled Septarian Nodule Benvel - Utah

This is a beautiful, cut, septarian nodule/geode collected West of Orderville, Utah. It has a gorgeous pattern due to the aragonite and calcite filling in cracks and a cavity lined with stunning, calcite crystals. It has been cut at a 45 degree angle and polished exposing the crystal lined cavity. It sits nicely on a flat surface for display.

About Septarian

Septarian or septarian nodules are concretions containing angular cavities or cracks, called "septaria", filled with calcite and aragonite. A concretion is a hard, compact mass of rock that often forms around decaying organic matter. In the case of septarian nodules, the concretions formed around decaying sea life in a marine environment.

The exact mechanism for how the cracks form in the concretions is a mystery. One possible mechanism is the dehydration of the clay-rich core of a concretion, causing it to shrink and crack. The cracks could also be caused by gas expansion produced by the decaying organic matter within a concretion. Earthquakes have also been suggested as yet another mechanism.

The cracks in the concretions are then filled in with minerals such as calcite (yellow), aragonite (brown), and sometimes pyrite, causing very interesting patterns. They have often been described as looking like dragon's skin. They are frequently found as geodes with hollow, calcite crystal-filled cavities. More rarely, the fossils that originally started the formation of the concretion are still preserved in the septarian.
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DETAILS
SPECIES
Septarian
LOCATION
West of Orderville, Utah
FORMATION
Frontier Formation
SIZE
Polished Face 6.4 x 4.5"
CATEGORY
ITEM
#80908