I know that only highest density planes help in showing peaks in the diffraction. Firstly I am not convinced why it diffracts and secondly with close reference to my question please explain me what causes diffraction peaks in X-Ray crystallography?
X-ray diffraction data represents the structure properties not the crystal shape except nanoscaled grains which is a function of half width maximum of the peaks. The knowledge on how X-Ray diffracts by the crystal planes is available in most solid state textbooks such as the one by Charles Kittle. Also it’s possible to find basic information from google search sites
XRD helps to determine crystal structure and shape factor of single crystal but not the shape. To find out shape of single crystal scanning transmission electron microscopy is used. Read the attached articles .