AMMO-C-01 Origin: Madagascar Grade: A Dimensions: Approximately 30-40mm Weight: Between 15 and 25g Origin: Madagascar Grade: A = good Very beautiful nacreous ammonite from Madagascar, approximately 30-40mm. The shapes, patterns, and colors may vary from one stone to another. 100 million years (Cretaceous) Origin: Majunga/Madagascar Name: Cleoniceras besairiei Ammonites are a group of fossil marine animals from the class of cephalopod mollusks. They can be several million years old. The shell is generally the only fossilized part. It appears in the form of a flat spiral with contiguous whorls. Some forms have a non-contiguous or helical spiral or are completely uncoiled, in which case they are referred to as heteromorphic ammonites.