The hardest mineral on Earth is diamond, which is composed of carbon atoms arranged in a crystal lattice structure. This unique configuration gives diamonds their remarkable hardness, rated 10 on the Mohs scale, which measures the scratch resistance of various minerals. Diamonds are not only prized for their beauty and used in jewelry, but they also have industrial applications due to their unmatched durability. They are utilized in cutting, grinding, and drilling tools, making them invaluable in various manufacturing processes. The geological conditions required for diamond formation are quite extreme, occurring deep within the Earth's mantle under high pressure and temperature.