Ammonites are prehistoric nautilus (extinct marine animals), related to the chambered nautilus, squid, cuttlefish and octopus family. They appeared 400 million years ago and thrived during the Palezoic and Mesozoic Eras.

Ammonites were able to swim due to the unique construction of their shell, which was divided into a series of air chambers, called phragmacones. The air in the chambers provided buoyancy for the animal to float, and like modern cephalopods, they probably moved through the water using jet propulsion. The animal lived only in the outer chamber.

There are several hundred species of ammonite fossil found around the world. These amazing prehistoric sea creatures ranged in size from under an inch to 9 feet (3m) in diameter. As different species of ammonites lived during different time periods, scientists can use these animals to determine the relative age of the rocks in which their fossils are found (such fossils are called “index fossils”). Because ammonites lived exclusively in marine environments, their presence also indicates the location of prehistoric seas.

Most ammonites are found in the Sahara desert in Morocco, when the Sahara was covered by a vast ocean hundreds of millions of years ago. Today, the Sahara harbours a wealth of different fossils. Ammonite fossils usually have their original shell preserved and are quite beautiful. Their coiled shell was made of calcium.

Ammonites died out 65 million years ago, along with the dinosaurs. The name “Ammonite” is derived from Ammon, an ancient Egyptian god who was depicted with ram’s horns behind each ear.

Ammolite is the preserved mother-of-pearl of the Ammonite fossil that has gone through a geological and mineral transformation and can be found in the Black Bearpaw Shales of Southern Alberta, Canada. Many collectors prize the light refracting qualities of this gemstone, which appears rainbow-hued.