Polarity of reticular faces and the thermodynamic state of the face system of a crystal

A new concept is introduced into crystallography – the polarity of the reticular faces of a crystal. Reticular faces are divided into basic and additional. The basal faces, systematic in a facet system, only increase as the crystal grows. The shape of the crystal is invariant, stable within the limits of its stability and does not affect the state of its equilibrium. Additional faces, on the contrary, shrink and disappear, and therefore are variable extensive parameters of the facet system. They do not form their own system and associate with the basic ones, determining the variation of the facet system. The polar system is nonequilibrium, spontaneously and irreversibly transforms into the final basic facet system and is in quasi-static equilibrium. The habit of a basic crystal of an invariant shape changes during its growth according to the mechanism of translational symmetry.