How does Graphite differ structurally from Diamond, resulting in a large difference in hardness?

Answer

Graphite has 2D sheets held by weak forces; Diamond has a 3D covalent network

Graphite's strong covalent bonds exist only in two-dimensional sheets held together by weak van der Waals forces, allowing them to slide; Diamond has covalent bonds in a continuous three-dimensional matrix.

How does Graphite differ structurally from Diamond, resulting in a large difference in hardness?
mineralstructurecontrolhardnessbond