Caltech professor Julia Greer and her team have taken a really close look at diatoms and found them to be tougher and more resilient than previously thought. Diatoms are single-celled, mostly microscopic algae encased in hard shells made of silica called "frustules." To figure out just how durable they really are, Greer and her team made beams out of frustules and conducted three-point bending experiments on them. According to their tests, it has the highest specific strength among all known biological materials. In other words, it has higher strength-to-weight ratio than bones, teeth and even antlers, all of which are known for being sturdy.