Vickers hardness (H V ) was predicted using four pertinent theoretical models of hardness . The thermodynamic model is based on thermodynamic properties and crystal structure, while Mazhnik-Oganov and Chen-Niu models use the elastic properties. Lyakhov-Oganov approach considers topology of the crystal structure, strength of covalent bonding, degree of ionicity and directionality. The fracture toughness (K Ic ) was evaluated within the Mazhnik-Oganov model .