This question is brought about by this post:
Reasons for [crystallography]:
- There is a large amount of current mathematics devoted to crystallography ranging from inverse scattering, X-ray/Radon transforms, and especially the study of the phase problem
- The geometry of unit cells of crystal lattices is mathematical (the tiling problem in 3D).
- It is a somewhat special field at the intersection of group theory, linear algebra, Fourier analysis, and analytic geometry (perhaps more?)
Reasons against [crystallography]:
- It is a somewhat specialised field, and we may not get much call for questions of that sort here.
- Questions that would fall under this tag could in principal be tagged as a combination of other tags. (The question linked above could perhaps have the [tiling] and [analytic-geometry] tags added.)