Teeth of a chiton, a primitive marine mollusc that eats algae off the rocks. To be strong enough to scrape rocks all day their teeth are reinforced with iron (shown in orange) and are constantly being replaced. Roll over the micrograph (left) to see a photograph of a chiton in a rockpool. A conveyor belt of teeth along the chiton's underside is continually renewing itself with iron-rienforced teeth. Scientists are learning from this, to develop stronger materials that combine the organic and the crystalline, for all kinds of new applications.