Crystals are repeating units, they look identical all the way down to a thing called the unit cell/space group. Obviously to us there can be multiple crystal units nucleating and growing off one another and so they appear to make distinct unique shapes but each of those are single crystals with the same shape, assuming a homogenous sample.
If the macro crystal is a cube, you can observe that all he way down to the arrangement of core atoms in the shape of a cube. That is difficult to see even with electron microscopy though and the only way to truly see it is indirectly using synchrotron radiation/X-Rays.
Source: PhD in molecular biophysics studying crystal structures.