Ammonites appeared in the fossil record approximately 240 million years ago during the Triassic period and disappeared around 65 million years ago at the end of the Cretaceous. They were predatory mollusks related to the Nautilus and modern-day Squids.

This specimen is Discoscaphites conradi, found in the Fox Hills Formation of South Dakota. It lived during the Upper Maastrichtian, Late Cretaceous era, around the time of the K-Pg extinction event that caused the extinction of all non-avian dinosaurs. Most species of Ammonites also went extinct during this era, but it’s believed the Discoscaphites genus may have briefly survived the extinction event before going missing in the fossil record.

Covered in a Mother of Pearl nacreous shell, the Ammonite’s opalescence is due to the Aragonite found in the shell. As light travels and bounces through the layers of Aragonite, a rainbow spectrum can be observed. Thicker layers of Aragonite can lead to deep shades of red and orange, while thin layers can display shimmering greens and dainty violets.

This Ammonite Fossil is 3 x 2 inches, and 4.25 inches tall.  Due to the fragility of the Ammonite's connection to its matrix, this item is Pick-Up Only from HMNS-Hermann Park. Local Delivery is available to the Greater Houston area.