The element used in pencils is graphite. Graphite is a form of carbon that is soft and slippery, making it ideal for writing and drawing. Pencils typically consist of a core made of a mixture of graphite and clay, which is encased in wood or a similar material to facilitate ease of use. The ratio of graphite to clay determines the hardness or softness of the pencil, influencing the darkness of the mark it leaves on paper. Graphite is prized not only for its use in pencils but also in various applications ranging from batteries to lubricants due to its unique properties.