Diamonds are most commonly associated with carbon, which is the element from which they are composed. Carbon atoms bond in a crystal structure, creating the strong and beautiful gemstones we know as diamonds. Formed deep within the Earth under extreme pressure and temperature conditions, diamonds can be found in a variety of colors, although the classic and most recognizable form is colorless. Carbon's unique properties contribute to the diamond's hardness, making it the hardest natural substance known. This quality, coupled with its brilliant refractive abilities, makes diamonds highly sought after for jewelry and various industrial applications.