Ammonite & Ammolite

March 06, 2021 3 min read

Four hundred million years ago the Earth was very different to what we know it as today. Little did the thriving creatures of our planet back then know that not only would they be a stepping stone in the evolution of life, but they would also provide future generations with fabulous jewelry.)

Ammonites are Cephalopods, an extinct group of marine invertebrate animals, which thrived in tropic seas spanning from the Devonian geological period (circa 400 million years ago and became extinct at the close of the Cretaceous period along with the Dinosaurs.

Ammoliteis a rare, vividly colored iridescent gemstone made from the shells of Ammonites that have been compacted, crushed and heated through aeons of tectonic upheaval. This results in a bright, fiery prismatic colored gemstone with metaphysical properties helpful for stability and protection.

The Ammonites that form Ammolite once inhabited a prehistoric inland subtropical sea that bordered the Rocky Mountains of North America and Canada. As the sea receded, layers of sediment buried the Ammonites. This sediment preserved the Aragonite of their shelled remains, preventing it from converting into calcite or Pyrite through the process of pseudomorphism.

Pseudomorphism refers to a process where one mineral replaces another whilst retaining its form and dimensions. In the case of Ammonite shells which comprise of a number of minerals including small Argonite platelets, the same mineral responsible for the nacre of pearls, are often replaced by pyrite or calcite which in turn creates beautiful cavities of crystalline material throughout the shells structure. Ammonites themselves make beautiful and interesting pieces of jewelry but it is the Ammolite that is the most desired aspect of these ancient creatures. 

The vivid iridescent sheen of Ammolite is caused by the interference of light that refracts and reflects back from the layered Aragonite platelets within the stones structure. The thicker these layers are the more reds through green hues are seen and when they are thinner the violet and blue hues dominate. This iridescence is often confused with the ‘Labradorescence’ of labradorite and the spectral ‘play of colour’ of Precious Opal.

Due to the Ammolite layer of the shell usually being mere fractions of a milimetre in thickness, most Ammolite gems are in fact composite stones and are generally in the form of a doublet or triplet. The thin layer is adhered to a dark backing material being its matrix or mother rock from which the Ammolite is quarried. As the Ammolite is thin and fragile a second layer is added to protect the stone and in turn enhance the optical display. This is generally a synthetic Spinel, synthetic Corundum, synthetic Quartz or a glass type material. 

Bunny Bedi, owner and designer at Made in Earth, discusses his experiences when working with this organic gemstone.

“Ammolite has been a stone I have desired to have in our expansive gemstone jewelry collection for many years. It is quite an expensive gemstone due to its rarity and because of this high quality pieces are generally suited to a gold setting along with Diamonds and other precious stones.

“Given the stones fragility and hardness of just 4.5 – 5 we need to be extremely careful whilst fashioning each piece and thought must be taken with the design and style of each setting. By ensuring a solid setting, protecting the stone’s edges from being exposed, a bezel setting is mostly used. Using doublets with a Quartz overlay means each stones surface hardness is that of Quartz and will greatly extend the durability for our customers.

“Ammonites remain in our collection as a favorite fossil in our gemstone jewelry collection and it’s nice to be able to show our clients where the Ammolite comes from.”

Ammolite is a magnificent gemstone with an incredible history of creation over millions of years. Through the incredible feats of nature, even the most unsuspecting creatures can transform over time to become one of the most rare and beautiful minerals for use in jewelry. The value of good quality pieces will continue to increase for collectors and gemstone lovers and as time passes new and wonderful gemstones will continue to form unsuspectingly beneath the earth’s surface. 


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