Crystallography. Introduction to the study of minerals / Кристаллография. Введение в изучение минералов

In this part, Chaps. 1 to 5, the crystal is studied as an ideal entity, from a geometrical point of view through the concept of lattice. The geometry and symmetry of the lattices and the external morphology of the crystals are considered. From a macroscopic point of view, the crystal is considered a homogeneous and continuous, anisotropic and symmetrical medium. When the internal symmetry is studied, the crystal is considered a homogeneous and discrete medium, as well as anisotropic and symmetrical.
In this block, it is important to understand the importance of some features. First, it is important to abstract in crystallography. Considering a reference system (e.g., crystallographic coordinate system), the following two situations are equivalent: (1) move (translate) the reference system and leave the crystal static or (2) move (translate) the crystal and leave the coordinate system static. The crystal can be described from a geometrical point of view, through the lattice, not only in an unlimited way, but also in a limited way, with the concept of cell, which is the smallest space of the lattice limited by the fundamental translations, which are the smallest distances at which the crystal motif (ion, atom, molecule or groups of them) is repeated in the three-dimensional space. <...>