The hardest mineral known to humankind is diamond. Formed under extreme pressure and temperature conditions deep within the Earth's mantle, diamonds are made entirely of carbon atoms arranged in a crystal lattice structure, which gives them their exceptional hardness. Their hardness is measured using the Mohs scale, where diamonds score a perfect 10, making them ideal for various industrial applications, including cutting, grinding, and drilling. Beyond their industrial use, diamonds are highly valued as gemstones for their brilliance and rarity, often symbolizing love and commitment in jewelry, particularly in engagement rings.