Ammonites are a well known fossil with spiral form, ribbed partitions. They lived in the oceans millions of years ago. Ammonites belong to a group of predators known as cephalopods. Ammonites began life as tiny planktonic creatures. They would have been vulnerable to attack, they quickly grew a strong protective outer shell that shielded their soft interior from damage. They grew in size rapidly, with females growing larger than the males. As the Ammonite grew, new chambers were added behind the head chamber.

Ammonites moved by jet propulsion, expelling water through a funnel-like opening to propel themselves in the opposite direction. They typically lived for couple of years, with some species lasted longer and grew very large.

Some Ammonite fossils bear intricate patterned details on their outer surface called Sutures. Suture patterns are very useful for distinguishing different species of the Ammonites.

They are commonly found as fossils, formed when the remains or traces of the animal became buried in sediment which later solidified into rock.

Most Ammonite specimens today are located, cleaned and cut in half, then are polished. When the outer shell is polished, they often have a nice pearlescent finish to them.