I think the difference between A graphite pencil,pen,and charcoal are that. Pencil is use for skecht and pen is used for a more darker color. While charcoal seems more darker and it can be easy to recreate when you mess up on a pecies of drawing. Pen on the other hand u won't be able to erase your mistakes but it is darker. Pencil you can erase your mistakes. And if you come up with an idea and don't like the one you have u can erase and recreate.