Diamond is made of the chemical element carbon. In its crystalline form, diamond exhibits a crystal lattice structure where each carbon atom is bonded to four other carbon atoms through strong covalent bonds. This arrangement gives diamonds their exceptional hardness and brilliance, making them one of the most sought-after materials for jewelry. Natural diamonds are formed deep within the Earth's mantle under high pressure and temperature over millions of years. While diamonds can be synthesized in laboratories, their fundamental composition remains carbon, showcasing the remarkable versatility of this element in creating such a beautiful and enduring material.