The shape of a graphite crystal is hexagonal. Graphite is a form of carbon that consists of layers of carbon atoms arranged in a hexagonal lattice. The layers are held together by weak intermolecular forces called Van der Waals forces. Each carbon atom is bonded to three neighboring carbon atoms in a trigonal planar arrangement, resulting in a flat hexagonal structure. This gives graphite its characteristic layered structure, which makes it useful as a lubricant and as the "lead" in pencils.