Crystal Morphology and Crystal Symmetry

Abstract

Crystallography grew up empirically as a branch of mineralogy. It was supported by laws deduced from observations, such as the law of constancy of interfacial angles and the law of rational intercepts, and involved mainly the recognition, description, and classification of naturally occurring crystal species, that is, it was a study of the morphology, or external form, of crystals. By the end of the 19th century, it was believed that crystals were composed of orderly arrays of atoms and molecules and, on this basis, Federov, Schönflies, and Barlow, independently, concluded that there were only 230 ordered spatial patterns, or space groups, based on the 14 crystal lattices deduced earlier by Bravais.