Carbon is one of the most important chemical elements. Industry uses it in a wide variety of products, and all living things are based on carbon. Without carbon, life would be impossible! Yet carbon makes up less than 0.03 percent of the earth's crust. Pure carbon exists in nature in the form of diamonds, and in graphite. Both forms are pure carbon with different crystal structures. Another form of pure carbon, called amorphous carbon, consists of graphite-like particles too tiny to see without a microscope. Diamonds and graphit ....