The hardest naturally occurring material is diamond. Formed deep within the Earth's mantle under high pressure and temperature, diamonds are made of carbon atoms arranged in a crystal lattice structure, giving them exceptional hardness. This property allows diamonds to scratch nearly all other materials, making them highly sought after not only for jewelry but also for industrial applications such as cutting, grinding, and drilling. Because of their rarity and beauty, diamonds have been treasured throughout history and symbolize wealth and status in cultures worldwide.