Ammonite is a marine animal related to such as octopus, squid and cuttlefish, the modern animals we know today. Most people know of the "Jurassic" term. It's the era where the dinosours live. Expert said that before Jurassic era there was Triassic era where an abundant of Ammonites live. But the first Ammonite mollusk appeared before the Triassic era, and the expert called it Devonian era. So we can say the appearance history of Ammonites is older than the appearance of Dinosours. Ammonite fossils found in many different places such as Madagascar, Canada, Morroco, Australia, etc.
In general, there are two types of Ammonite fossil, one that has an opal-like shell and the other has a regular shell. The opal-like shell called Ammolite. The fossil Ammonite we have is not an opal-like shell, but after polished, we can see more pattern compare with the Ammolite. Mainly there are three types of Ammonite we produced, which are full-polished, half-cut and slab. The bigger size is for a room decoration or a collection, while the smaller size which already cut here and there is meant to be used for jewellry such as a pendant and ring.
It's unimaginable when today we see the fossil of one of the oldest animal on earth.