The mineral primarily used in pencils is graphite. Graphite is a form of carbon known for its ability to easily leave marks on paper, making it ideal for writing and drawing. This mineral is characterized by its layered structure, allowing for smooth and precise writing. Its use in pencils dates back to the 16th century when it was first discovered in Borrowdale, England. Today, graphite remains a core component of pencil manufacturing, demonstrating its essential role in education, art, and everyday communication throughout history.