Crystals

Abstract
THE CONCERN of modern crystallography is with the atomic theory of matter in all states of aggregation and with the optical principles of the diffraction of short‐wavelength radiation by such matter. This broad definition is a far cry from the morphological emphasis of early classical crystallography; it is, however, just a logical extension of concepts initiated by Max von Laue's demonstration in 1912 of x‐ray diffraction by crystals. Not only can the physical properties of a crystal be interesting; they can also be esthetically pleasing (figure 1). To probe a crystal one can use neutrons, x rays, electrons and now, protons. But crystallographers are scrutinizing the accuracy of their measurements. Improvements in crystal growing are leading to new solid‐state research, and huge biological molecules are being unravelled crystallographically.