How Crystals Grow

Abstract

THE answer to the question “How do crystals grow?’ is that we do not know ; but examination of some crystals growing may show what the difficulties are. We note first of all that crystals are very symmetrical and bounded by smooth faces, although, as Prof. S. Tolansky has shown, even on apparently quite smooth faces there are irregularities in the form of plateaux and pits. These smooth faces and sharp edges result from an inner order ; the molecules, atoms or ions which form the crystal are present in an orderly lattice, and a crystal can be regarded as made up of regular sheets or strips of the substance of which it is formed. The architecture can be revealed by X-ray, electron and neutron diffraction.