From Sea to Stone: Exploring the Different Types of Ammonites

Have you ever wondered about the types of ammonites that existed? These extinct marine mollusks came in a variety of shell shapes, sizes, and ridges. Some were tightly coiled, others had loose spirals or even straight forms. You’ll also find differences in ornamentation—some smooth, others ribbed or knotted. Over time, certain types fossilized into stone, while rare ones became opalized, transforming into radiant specimens. Their diversity reflects Earth’s complex evolutionary history. Many of you will enjoy identifying and collecting different varieties. Tree of Life Gems showcases brilliant examples of whole-shell ammonites from Madagascar.