In this work growth and characterization of potassium chloride with nanodiamond is studied. Crystals were grown in Czochralski crystal growth method. KCl crystals are doped with 0.5, 1 and 1.5 percent nanodiamond (ND) impurities. Breaking cross sections of the pure and doped crystals were characterized by (scanning electron microscopy) SEM. As a result, increasing the doping percentage of the ND in the KCl crystal, leads to arising the surface roughness and nicks curvature on the fracture cross section of the crystal. It means that ND doping inside KCl crystal caused to increase mechanical hardness of the crystal and increasing the doping percentage results more mechanical resisting crystal. On the other hand, Vickers microhardness scale is used in this study. Hardness is too complex to be described by first principles. Based on the dielectric chemical bond theory, a semiempirical theoretical formulation of the hardness of pure and doped crystals is introduced. Analyzing of the results shows increasing of the nanodiamond doping leads to increasing of mechanical resistance of the samples.