More than 2500 different minerals are known in mineralogical sciences. It is an amazing fact that all these minerals fit into only 32 crystallographic point groups constituting seven symmetry classes. These crystallographic point groups, the groups of rotations and inversions compatible with translational symmetries, mainly determine the macroscopic morphology of mineral crystals.
The manifest morphology of a crystal is determined by the faces that are expressed in a crystal. A crystal face is described by its intercepts with the crystal axes. Due to the symmetries of the point group of a crystal, one needs to know the indices of only some of the crystal's faces, since the remaining faces are determined by the symmetry operations of the point group.
In practice, one often wishes to display a crystal's morphology on the basis of its point group, the crystal's axes system, and the indices of its symmetrically distinct faces. This is exactly the aim of the package Mathematica package Crystal.m presented here. I hope that it will be especially useful for those who want to train their three-dimensional imagination and to acquire a feeling for the relation between the morphology of crystals and the underlying point group and face indices.

You may download the zipped file Crystal.zip including the package crystal.m, an example notebook, a manual, and mineral data. I would appreciate any comments or bug reports.