Also on these boards
ammonite: Per Wikipedia the ammonites went extinct with Dinosaurs 65 million years ago. Ammonites survived until the end of the Cretaceous period in a sea that covered what is now Alberta. Canada and Montana, USA. These ammonites were transformed into the rare gem known as Ammolite.
Variety is shown in this picture with the different types of sea shells. The different lines and colors of the shells also add the the principle of variety. Each shell is placed differently in the way that it is set up making each shell different but also creating a sense of unity.