4.7" Polished Utah Septarian Sculpture - Beautiful Yellow Crystals
This is an absolutely stunning piece of septarian that has been polished into a free-standing, flame shaped sculpture. The septarian was mined West of Orderville, Utah and was deposited during the Jurassic period, 150 million years ago. It has a gorgeous pattern due to the aragonite and calcite filling in cracks and the quality of the polishing work is exceptional. Excellent deep crystal pockets in this piece.
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. Another is the cracks being due to the expansion of gases produced by the decay of organic matter within a concretion. Earthquakes have also been a suggested as yet another mechanism.
The cracks in the concretions are then filled in with minerals such as calcite (yellow) and aragonite (brown) and sometime pyrite causing the very interesting patterns, which have often been described as 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.