Beautiful huge ammonite douvilleiceras, 13.5kg. Specimen from masagascar. A natural fossilized enamel, some parts with purple iridescence and perfect spiral shape making this fossil even more rare and valuable. Truly a beautiful, wonderfully preserved specimen. This is an extinct cephalopod mollusc belonging to the ammonites. It lived in the Upper Jurassic (172-149 million years ago), and its fossil remains are found on all continents. Ammonites were ancient marine cephalopods, similar to today's squids and octopuses, but with a defining feature: their distinctive, tightly coiled spiral shells. These shells, resembling those of modern nautiluses, served as both a protective home and a buoyancy aid, allowing ammonites to navigate the prehistoric seas with ease. First emerging around 240 million years ago in the Triassic Period, ammonites thrived for over 175 million years, adapting through numerous forms and sizes. As predatory creatures, they likely fed on smaller marine organisms, using their tentacles to capture prey. However, their long reign came to an end 65 million years ago at the close of the Cretaceous, coinciding with the mass extinction event that also eliminated the dinosaurs.