True
Explanation:
In diamond C-atoms are sp3 -hybrid due to cross-linked three dimensional structure (closely packed structure). In graphite C-atom are sp2-hybrid, so graphite is made up of layers of hexagonally linked C-atoms arranged above and below to each other and bonding between layers is due to van der Waals' forces thus the graphite structure is more open than that of diamond. Hence, graphite is less hard than diamond.
