Large Ammolite Fossil

Ammolite Fossils: North Dakota’s Iridescent Treasures of the Cretaceous Seas

Ammolite, a rare and stunningly iridescent gemstone derived from fossilized ammonite shells, stands as a vibrant relic of the Late Cretaceous period. Found in regions like North Dakota, these fossils date back approximately 70 to 75 million years, when vast inland seas covered much of North America. Ammonites, the extinct marine mollusks responsible for Ammolite, are renowned for their spiral shells and their close relation to modern cephalopods such as squids and nautiluses.

What makes Ammolite particularly captivating is its kaleidoscope of colors, ranging from deep reds and oranges to radiant greens and blues. This dazzling play of light results from the unique mineral composition of the fossilized shells, combined with millions of years of geological processes. Ammolite is not only a geological wonder but also a cultural symbol, revered by Indigenous peoples for its spiritual significance and believed to bring good luck and prosperity.