Paua shell

This is a detail of a paua shell (also known as abalone). They are quite common on the beaches in New Zealand and their sea snail inhabitants are a prized food. You can even buy paua fritters with chips from many fish and chip shops. (edit: although this is not especially recommended..see FirehorseMia's comment below)

The Maori people value paua as a seafood and the beautiful blue, green iridescent inner surfaces of the shell are often used in Maori carvings to form the eyes.