Ammolite – Semi-Precious Gemstone
Did you know that Ammolite is one of three uniquely declared semi-precious gemstones named in the last 300 years?
Dating back over seventy-one million years, Ammolite originates from a crustaceous shell. It is an iridescent, nacreous layer of a crustaceous shell that is found specifically in the Bearpaw Formation. The gemstone formed from the fossilization of marine cephalopods, a squid-like organism with a coiled shell back, which were present during the Jurassic and Cretaceous period. Over time due to the chemical composition of the earth and pressure, the gem formed.
Ammolite is primarily found in Alberta, Saskatchewan and Montana, and occurs in sufficient quantities for it to be mined and produced, making it economically significant. Southern Alberta, currently is the only place that Ammolite is commercially mined today as it produces the clearest and richest tones of the gem. Korite is the largest commercial miner and producer of the Ammolite gemstone.
Ammolites Unique Colour
Ammolites radiant colour is due to an incredible optical phenomenon recognized as iridescence. Iridescence exhibits a breathtaking play-of-colour comparable to opal. Ammolite colour varies according to the angle of light and the viewing angle; the variety of iridescence ranges from minor to extreme colour changes. Ammolite also has chromatic colour shifts, such as red to green, or green to blue. The chromatic shifts can be monochromatic (singular), dichromatic (double) or spectro-chromatic (multiple) and the most cherished Ammolite shifts through the complete colour spectrum.
Ammolite layers are typically thin; they are predominately made up of soft aragonite and CaCO3, yet the layers are surprisingly durable and can be polished and manufactured into beautiful jewellery.
Ammolite is one of the only naturally occurring iridescent materials that is strong enough to be manufactured into jewellery, making Ammolite one of the most unique gems on earth. As noted above, iridescence is the property that generates the unbelievable “rainbow” of colours throughout the exterior layer of Ammolite. The fossil shell is made up of tightly-packed, flat crystals of aragonite that are integrated into thin “scales”. The layers of crystals do vary in size, and the thickness of the crystals translate into the clarity and intensity of the colour of the gems. The most economically valuable Ammolite gems and Ammolite crustaceans have constantly changing colours, as the position of the light changes when moving the stone.
First Historical Reference To Ammolite
It is important to note that the first historically recorded instance of Ammolite being recognized as a gemstone only dates back to 1962, while the presence of the stone has been documented historically since at least 1908. “Ammolite” has also been recognized as “Aapoak” which was the trade name given to what we know today as Ammolite by the members of the Blood Indian Band; Aapoak is derived from the Siksika language, meaning “small, crawling stone”. Unfortunately, we do not have clear historical record of how long the Blood Indian Band recognized this stone as a gem. In 1981 Ammolite was officially recognized as an organic gemstone by the Coloured Stones Commission of the World Jewellery Confederation.