Acta Petrologica et Mineralogica

The crystal chemical mechanism of mineral cleavage/fracture and its relationship with interplanar spacing were quantitatively studied using density functional theory, broken bond theory, and crystal chemistry properties. It was found that the common cleavage/fracture planes of minerals do not always correspond to the crystal planes with the maximum interplanar spacing, showing a weak correlation. The theoretical calculations suggested that the common cleavage/fracture planes of minerals correspond to the crystal planes with the lowest surface energy, and the surface energy is positively correlated with the reticular density and the average broken bond number τ of the crystal plane atoms. The interplanar spacing is positively correlated with the reticular density, implying that when crystal planes with large interplanar spacing become common cleavage/fracture planes, the surface energy needs to be reduced by decreasing the average fracture bond number τ of the crystal plane atoms. However, the analysis revealed a poor correlation between the interplanar spacing and τ, which indicates that the interplanar spacing is not directly related to the cleavage/fracture patterns of minerals. The results of this study can provide theoretical insights for research on the cleavage/fracture patterns of minerals and surface properties.

interplanar spacing; cleavage/fracture nature; surface energy; broken bond parameters; weak correlation