Nacre, or Mother of pearl is the iridescent lining you see on the inside of an oyster, mussel, or abalone shell. It is also the same material that creates pearls. The play of light we find so appealing is a result of the little beasties engineering the shell down to the molecular level. To create a shell that is tough and lightweight (sometimes 3000 times tougher than its component parts), the abalone layers an organic material and a non-organic material into a nano-structure design resembling brick and mortar.
We have seen before how the abalone inspired super tough materials. Now engineering professor Nicholas Kotov and his team from the University of Michigan have created a process similar to our bivalve friends that allows the creation of materials one nano-layer at a time, with impressive results.