Uses of Carbon. Carbon (in the form of coal, which is mainly carbon) is used as a fuel. Graphite is used for pencil tips, high temperature crucibles, dry cells, electrodes and as a lubricant.Diamonds are used in jewelry and â because they are so hard â in industry for cutting, drilling, grinding, and polishing.arbon (in the form of coal, which is mainly carbon) is used as a fuel. Graphite is used for pencil tips, high temperature crucibles, dry cells, electrodes and as a lubricant.