X-ray diffraction (XRD) is the technique most heavily relied on in soil mineralogical analysis. X-ray diffraction is a technique that provides detailed information about the atomic structure of crystalline substances. It is a powerful tool in the identification of minerals in rocks and soils. So it is possible to characterisation of rocks and soil through XRD

Yes，of course.

The degree to which XRD can be used to clearly differentiate between different types of rocks and soil depends on a variety of factors, such as the complexity of the sample matrix and the mineralogical diversity of the sample. In most cases, XRD alone may not be sufficient to fully characterize a given sample, and other complementary techniques may be needed in order to gain a more complete picture of the sample's composition and structure.