Mineral Crystals And Structural Classification

Abstract

Crystallography is the study of the structure of crystals. It describes the structure of a crystal, the principles that govern the different types of possible structures, the crystal structures of specific substances, and the methods by which structures are determined. In numerous scientific fields, the knowledge of crystallography is essential and significantly important e.g. metallurgy, materials science, ceramics, physics and chemistry. Each of these fields has its own special requirements, but there is a basic core of knowledge common to them all. This consists of the description of the crystal structure in terms of the smallest unit representing it, the three-dimensional lattice with which the atom sites can be represented, and also the accepted method for determining planes and directions in crystal structures. Various aspects of crystallography e.g. symmetry, point groups and space groups, Miller indices, unit cell geometry, lattice, motif, planes and directions, crystallographic systems and forms, various crystal defects and symmetrical intergrowths of crystals called twinned crystals will be discussed to explain the crystal morphology and how it influences the various physical and chemical properties of minerals.