The pencil tool-bar is lead-free and it never has been. Pencils contain a form of solid carbon known as graphite. According to Henry Petrosky book, Pencil, graphite, pencil lead, it was first developed and popularized in the 1600s. Be the first to use the graphite is simply dug up, the mineral from the hills, and it was found that it could be cut into sticks and used as a perfect writing tool. For 1600 years, no one knew that the chemical nature of the material, such as, the chemistry was still in its infancy. Because of this, the written material was also, in the case of metallic lead, but he had a dark complexion, and people had begun to call the "black lead". In the end, the name of the pencil core is shortened to "stay the same".