The hardest known naturally occurring material is diamond. Composed of carbon atoms arranged in a crystal lattice structure, diamonds have exceptional hardness and are renowned for their brilliance and light-reflecting qualities. This unique arrangement of atoms confers both strength and durability, making diamonds not only valuable in jewelry but also useful in industrial applications, such as cutting, grinding, and drilling. Diamonds are formed deep within the Earth’s mantle under high-pressure conditions, and their creation can take millions of years.