11-1/2" Utah Septarian Bookends Agate Bookends The oldest blastoids lived about

The oldest blastoids lived about 425 million years ago

At the time

Streaks of warm browns and reds are indicative of iron oxides intermixing with quartz and other minerals during a specimen's fossilization process

amphibians and all other life in those wetlands (bogs) were suffocated by the ash and immediately there began a permineralization / petrification process

pyrite gives off sparks

11-1/2" Utah Septarian Bookends Agate Bookends The oldest blastoids lived aboutThese strange and handsome Geodes are from the Henry Mountains of Utah. Originally formed in an ancient sea floor some 50 70 million years ago, sediment collected around sea life as they decomposed, forming a concretion. Calcium carbonate from the shells of these creatures began to take a new form over time, creating calcite crystals and bands of aragonite. As the oceans receded, these mud balls hardened, shrinking and cracking in the sun. The gold