Paua

Paua is a shellfish (actually a large sea snail) and is a type of Abalone.
The bright irredescent blue green colour of the shell comes from their diet - food you can only get in the cool deep waters of NZ.
Generally the colder the water the brighter blue and green the shell is.
Paua is used a lot in jewellery and also in traditional Maori carvings where you can see Paua used for the eyes.