Redundancies are pointed out in the widely used extension of the crystallographic concept of Bravais class to quasiperiodic materials. Such pitfalls can be avoided by abandoning the obsolete paradigm that bases ordinary crystallography on microscopic periodicity. The broadening of crystallography to include quasiperiodic materials is accomplished by defining the point group in terms of indistinguishable (as opposed to identical) densities.

12 pages [The author apologizes for intruding on this archive, but suspects that this way of relaxing the definition of a group of transformations may be familiar to some of you in other contexts. He would welcome comments.]