FYI: What's The Softest Material On Earth?
Materials Varying In Hardness Wayne Scherr/Getty ImagesWe know diamonds are the hardest, but determining the softest stuff on the planet is complicated. Everyone knows the hardest material on Earth is diamond, says George Pharr, director of the Joint Institute for Advanced Materials at the University of Tennessee. But when it comes to the softest stuff on the planet, "there's no one definition," he says. Metallurgists and mineralogists might interpret "softness" to mean a material's tendency to deform under pressure and to stay in that deformed state. But that reading might come off a little wonky when you start looking at elastic materials, like rubber, which can deform and then regain their form. As a result of this ambiguity, researchers employ an array of hardness (or softness) tests, depending on what sort of material they're looking at. For minerals, they might use the classic (and exceedingly simple) Mohs assay, which involves...