Carbon

Carbon is a nonmetal whose atoms can form four bonds and link into chains and rings, creating the varied compounds essential to all known life. Even pure carbon can look very different: soft graphite and hard diamond contain the same element, but their atoms are arranged differently. Graphite conducts electricity, while diamond is an electrical insulator. Graphite mixed with clay makes pencil cores, while diamond is used in cutting tools. Carbon occurs naturally as graphite and diamond, and in compounds in living things, carbon dioxide, limestone, oil, and natural gas. Natural graphite is mined, then separated from crushed rock. Diamonds are also mined, but industry can make them using high pressure and temperature or by depositing carbon from gases.