The Symmetry Statistics of Mineral Species in Various Thermodynamic Environments

Abstract

This paper generalizes the data on the symmetry of minerals in different Earth shells as a function of temperature, pressure, and the combined effects of both parameters. It is shown that the distribution of mineral species in the symmetry hierarchy, in particular, the existence of a monoclinic maximum and a triclinic minimum in the symmetry statistics of the world for minerals and inorganic compounds, is determined, first of all, by two diverse factors: the dynamic properties of the crystal lattice (the number of unit-cell parameters that are not fixed according to symmetry) and the efficiency of the crystal structure (the maximum number of admitted atomic positions according to the given point-to-point group). As the temperature increases, the symmetry of a substance usually becomes higher, with constantly increasing pressure making it lower, but increasing again with its reconstruction. The mutual increase of temperature and pressure with depth inside the Earth provides a stable increase of the average symmetry of rock, from a few units to the maximum value of 48 of the Dolivo-Dobrovolsky index. Due to the multiparametric nature of the mineral-symmetry statistics we will leave some fluctuations of this function without comment until their verification over time.