The beautiful, iridescent ammolite is about to become the official gemstone of the Canadian province of Alberta. Found predominantly in southern Alberta, ammolite is uniquely associated with the province’s identity.
Ammolite is formed from the fossilized shells of molluscs, known as ammonites, which lived in an inland sea east of the Rocky Mountains. After sinking to the seabed, the mud that covered ammonites hardened over millions of years to become shale. The shell properties, combined with southern Alberta’s unique geology, transformed many ammonite shells into the ammolite that is mined and used for jewelry today.
The mineral composition of ammolite is similar to that of a pearl, and the iridescent, multicolor presentation is reminiscent of a fine opal.
Although ammonite fossils are present in many places around the world, ammolite has been found only in one place, the Bearpaw geological formation in southern Alberta, making it one of the rarest gemstones, according to the American Gem Trade Association.
Ammolite is one of the few biogenic gemstones, which means it is made by living organisms. Others include amber and pearl. Ammolite was given gemstone status by the World Jewellery Confederation in 1981.
Ammolite’s gem quality is based on its color spectrum and brightness, according to Korite, which is responsible for more than 90% of the world’s ammolite production. The ammolite from shallower layers of sediment is of a lower grade and consists of red and green colors, while the higher-grade gems come from deeper layers and include blue and purple hues.
“Alberta is world renowned for its fossil resources,” said Dr. Craig Scott, director of preservation and research for the Royal Tyrrell Museum of Palaeontology. “The designation of ammolite as Alberta’s official gemstone adds to this reputation, and speaks to the remarkable history of ancient life recorded in the rocks throughout the province.”
Ammonite shells have been collected by Plains First Nations for a thousand years, and are still collected by Blackfoot communities for sacred purposes.
Alberta’s government is introducing an amendment to the Emblems of Alberta Act to designate ammolite as the official gemstone of Alberta. Passing the amendment will recognize ammolite alongside other official emblems, such as the official bird (great horned owl), official mammal (Rocky Mountain bighorn sheep), official fish (bull trout), official tree (Lodgepole Pine) and official stone (petrified wood).
Credits: Photo of ammonite shell with ammolite. © Royal Tyrrell Museum of Palaeontology via alberta.ca; Ammolite jewelry photo by Korite International. Licensed under CC By-SA 3.0 via Wikimedia Commons.