Ammonite (Alberta)

Ammolite is Alberta’s official gemstone, and was added to the Emblems of Alberta Act I 2022 The rock in which ammolite is found is anywhere from 72 million to 75 million years old Ammonites are extinct molluscs that lived in the Bearspaw Sea that once covered most of southern Alberta and was part of an ancient inland seaway that split North American in two and ran from the Arctic Ocean to the Gulf of Mexico. Not all ammonites have ammolite. It’s thought that the gem’s exclusivity to Alberta owes itself to the particular conditions under which the rock around the ammonite formed and the way the specimens were preserved. “Mineralization will start to happen around the fossil, and you end up with this ball of rock called a concretion encasing the fossil.

The best quality gem material is usually inside these concretions,” Alberta is the only place in the world where ammolite is mined commercially, and the Bearpaw Formation in southern Alberta is home to the highest quality of ammolite. The shores of the Oldman River and the St. Mary River are where ammolite is typically mined. Ammolite is prized for its iridescent appearance, a result of alternating layers of the mineral aragonite and the protein in the ammonites’ shells. Ammolite is formed from the fossilized shells of ammonites, which were ancient marine mollusks that lived millions of years ago.

Ammonites thrived in the oceans during the Mesozoic Era, primarily in the period known as the Cretaceous, between 65 and 240 million years ago. These creatures had coiled shells with intricate chambers that they used for buoyancy and protection. The process of fossilization and the subsequent formation of ammolite involves several steps. When an ammonite died, its shell sank to the ocean floor, where it was buried under layers of sediment. Over time, the shell was subjected to pressure and mineral-rich waters.

The minerals, particularly aragonite, which is a form of calcium carbonate, gradually replaced the original shell material, creating a fossilized replica of the ammonite’s shell. When the light passes into the shell, it hits these different layers or aragonite, then the light comes back to us and we see different colours. That’s what gives you the rainbow effect or iridescence. Very soft and brittle, ammolite must be stabilized with epoxy, and is often capped with quartz to help protect it when prepping for cabochons. Ammonite fossils are traditionally used for healing, luck, and as part of healing ceremonies by Niitsitapi (Blackfoot) peoples.

These ammonite fragments were given the name iniskim (buffalo calling stones) by the Niitsitapi. The gemstone is also used in feng shui practices. Ammolite is thought to “hold the knowledge of the universe” and bring auspicious forces into the home.