The average length of an unsharpened pencil is 7.5 inches, and smaller library or golfing pencils are usually 3 1/2 inches in length. Hexagonal-shaped pencils are a quarter of an inch thick at the smallest point.
While the name of the core of pencils is "lead," they are actually a mix of graphite and clay. Pencils likely never contained lead, but graphite was thought to have been a type of the metal and was called lead ore. The eraser on the end of the pencil was first patented in 1858, but the patent was declared invalid by the United States Supreme Court. The metal fastener between the eraser and the pencil is called a ferrule.