The origin of ammolite dates back about 70 to 75 million years ago when a number of smaller tectonic plates began sliding under the North American plate which caused the formation of the northern part of the Rocky mountains in what is now the northwestern part of North America.

With the Western interior seaway to the east of the mountains, rain started washing shale sediments into the seaway and over time formed the Bearpaw formation.
The western interior seaway was host to a large array of marine fauna, with one of the more odd-looking creatures being the “ammonite”. Ammonites were squid-like creatures with a coiled shell. When these creatures died and reached the sea floor their shells were covered by shale sediment, forming concretions around them.

The size of Alberta's Ammolite resource is difficult to assess. Searching outcrops does not yield reliable information because weathering has destroyed and altered much of the original Ammolite. The productive zones in the Bearpaw Formation are only a few feet thick, and the gem material is concentrated in large fossils. This makes drilling an ineffective exploration method.Iridescent ammonite fossils are found in many outcrops of the Bearpaw Formation, but these are often too damaged by weathering to serve as good gem materials, let alone complete specimens. The best gem-quality material is found in the excavations of mining operations where depth has protected the Ammolite from weathering. Some of it still requires stabilization to be used as a gem material. Some of it is too thin for use in manufacturing.In areas where there is a potential for gem-quality material, the Bearpaw Formation is typically dipping. This limits mining to a thin zone between the outcrop and where the overburden is too thick to mine profitably. This limits the size and value of any discovery. Together, these facts make Ammolite a uniquely rare material.

Once prospecting pays off and miners discover a concretion that contains gem-quality ammolite the specimen is carefully moved to a site for processing where the matrix surrounding the ammolite is meticulously removed being very careful not to damage the thin layer of ammolite it surrounds. Once one side of the ammolite is uncovered it is inspected, paying close attention to the stability of the piece and whether it is safe enough to start removing the matrix on the other side. This may not always be the case since the fossils themselves have been subjected to large amounts of pressure when they got covered in sediment and are very often broken and compressed. This makes it exceedingly rare to find a completely intact ammolite fossil. Preparators always hope to uncover a specimen that is complete on both sides and displays the entire color spectrum.

Interprospekt is a company that prides itself on ethical and sustainable mining practices around the world and partnering up with local people to enrich the local communities. Interprospekt as a company has over many years built up a very good relationship with the blackfoot natives that own the land and mineral rights to a large part of the Bearpaw formation. This relationship eventually lead to a fairtrade agreement being set up between them, making interprospekt the premier source of world-class ammolite specimens.

Click here to read the full article 'Ammolite - Ancient Origins of a modern Opal-Like Marvel by our gemmologist Andor Koot