With its bright rainbow play of color, ammolite is sure to draw attention. Once worn by members of the Blackfeet tribe to aid in hunting buffalo, this gem is a newcomer to the world jewelry market. Ammolite is the gem-quality aragonite shells of ancient ammonites, a mollusk which thrived on the bottom of the sea covering much of America 70 million years ago. Now found in the Bearpaw formation of the Rocky Mountains, these shells were preserved as the beautiful gem material we know today. After entering the market in 1969, ammolite became an official organic gemstone in 1981.

Learn about this unique gem’s quality factors before embarking on your next ammolite buying trip.

Ammolite Buying and the Four Cs

Although ammolite grading differs from other colored gemstones, the four Cs still prove useful for understanding ammolite quality.

The IGS ammolite value listing has price guidelines for ammolite naturals, doublets, and triplets.


Color is the most important factor in ammolite quality. Higher quality ammolite exhibits more, brighter colors, greater iridescence, shifting color with different viewing angles, and color regardless of the gem’s rotation.

Number and Rarity of Colors

Ammolite can display any color of the rainbow, but specimens that…