The body of the brittlestar Ophiocoma wendtii is studded with tiny crystalline lenses made of calcium carbonate. Microlenses like these are of great interest technologically, yet they have always been extremely expensive to produce. However, scientists from the Max Planck Institute of Colloids and Interfaces and colleagues from other institutes took their cue from biology and came up with a relatively simple and inexpensive method of producing calcium carbonate lenses packed together in a regular arrangement.
