Abalone shell. Coloured scanning electron micrograph (SEM) of a section through an abalone (Haliotis sp.) shell. The majority of the shell is composed of layers of overlapping platelets of calcium carbonate crystals, or aragonite, (grey). Between the layers are thin sheets of protein (not seen). This structure makes the shell much stronger than the materials would be in any other arrangement. Material scientists are trying to recreate this structure in the lab for use in body armour. Abalones are edible molluscs found in warm seas. Magnification: x1500 when printed at 10 centimetres wide.