In ancient times, people used charcoal, clods, etc. to mark on the stone very early in order to record the language, but the traces left too thick and easy to fall off, so people found lead. Lead is a silvery white soft metal. Lead is exposed to oxygen, carbon dioxide and water in the air. The surface will quickly turn into dark gray. It will leave a trace of gray on the paper and pull the lead into silk. This is the pencil.
However, this kind of pen is not ideal. One is light color, and the other is easy to cut the paper. In the 16th century, graphite was found. It was more convenient and cheaper to use the pen than lead, so graphite gradually replaced lead, but the name of the pencil was passed down.
Now mainly contains carbon.