Bragg's Law (above) explains the relationship between the wavelength of the rays (λ), the diffraction angle (sinθ), and the lattice spacing (d) in the substance Bragg Diffraction Equ.... Interference patterns are collected by the detector and processed to produce a graphical data set of the lattice structures, displayed in reference to the structure's d-spacing. XRD is also more often than not a useful tool for sample identification due to the fact that minerals all possess unique d-spacings. Therefore, the collected XRD data can be matched with references at specific angles and intensities to determine the composition of the sample.

Similarly to both the Raman and physical property tests, the XRD data essentially proves that the unknown sample is truly axinite. While there was some variation between the sets of data in Figure 2, the XRD data in Figure 3 shows just how closely the collected data and the referenced data match up. While the minor variations can be explained under the same pretense as variations in the Raman data (slightly differing composition compared to pure substances), they are far less apparent in these sets. Moreover, the variations that may be caused by a slightly different ratio of Fe2+: Mn2+ are expressed in this data set in terms of relative intensity, rather than lateral shift.The only significant difference comes from the two sets of data not being normalized to each other in terms of intensity, however, it is clear that each peak occurs at nearly exactly the same reference angle (2 Theta).