Beautiful opalescent ammonite, ammolite from Canada, Alberta

An iridescent ammonite from Alberta, Canada, embedded in the black bituminous shale matrix of the Bearpaw Formation. The shell shimmers in deep red, golden green, and blue, a play of colors known in mineralogy as ammolite.

Ammolite is the only biogenic gemstone variety apart from pearl and amber, originating from the aragonite shell of Late Cretaceous ammonites of the genus Placenticeras. Over approximately 75 million years, the shell was transformed under pressure and within the sediments of Alberta into iridescent layers. Today, they produce light refraction similar to opal.

The Bearpaw Formation on the Saint-Mary River is the only deposit worldwide that yields gem-quality ammolite. Mining is under strict supervision by the Blackfeet Native Americans, whose land covers large parts of the deposit, and is limited to a few certified operators.

The color distribution visible here is known as the dragon-skin pattern, a rare structuring that only occurs where the original aragonite lamellar structure has largely been preserved. Most ammolites show monochromatic fields; multi-colored pieces like this are classified as premium quality.

A collector's item with paleontological depth and gemmological rarity, suitable for display in a showcase or as a centerpiece of a fossil collection.