Physics: Scientists create 'hexagonal diamond' harder than natural diamond

2026-03-16T13:08:57.000Z Researchers in China have made what they claim to be the first samples of pure hexagonal diamond, a theorized rare variant of superstrong diamond found in meteorites from shattered dwarf planets. Natural diamond, also called cubic diamond, has been considered the hardest natural material on Earth for so long that the Mohs hardness scale, which rates minerals' resistance to scratching, uses diamond as the scale's upper limit.