Chemistry
Properties of Covalent Network Solids: Diamond
Quick fact
Diamond is the only gemstone made of a single element: carbon. Its hardness on the Mohs scale is 10, the maximum, and it can only be scratched by another diamond.
Why this is interesting
You know diamond is the hardest natural material, but did you know its extraordinary strength comes from the same type of bonds that hold water molecules together? So why is diamond so much harder than ice?