Interesting Facts About The Ammonite Fossils Fossils of marine animals have played a major role in expanding our understanding of the world that existed millions of years ago. Among the most important and famous ones that continue to interest and fascinate the paleontologists are perhaps the fossils of ammonite. After all, these fossils serve as excellent index fossils when it comes to identifying and understanding the different geologic periods. Fossils collectors, too, love to get their hands-on ammonite fossils for sale because they essentially tell the history of life on earth. But that is not all. Ammonite fossils have amazed many people with their unique qualities. Along with being time markers for geologists and other experts, they also serve as great showpieces for homes, given their attractive shape and fascinating history. Here are some very interesting facts about ammonite fossils: Ammonites were marine creatures that can be considered to be in the same family as that of octopuses and squids, the difference being that it had shells made from aragonite, a mineral that is also found in pearls. The invertebrate sea creatures first appeared around 240 million years ago, descending right from their ancestors, the straight-shelled cephalopods known as ‘Bacrites’. The ammonite shells are all held in high regard in the Chinese culture. Many of them still purchase ammonite fossils for sale to keep them in their home, believing that it will ward off negative energies and bring them good luck. Ammonites slowly disappeared around the time of the great dinosaur extinction at the end of the Cretaceous period, more popularly known as the K/T extinction event. It was only recently discovered that the female ammonites were much larger in size than the male ones, given that they had to reproduce. In Medieval Europe, it was believed that ammonites were actually coiled serpents. And it was because of this that they were given the name ‘serpentstones’.