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Written Artefact Profiling Guide
Written ArtefactProfiling Guide

Photo: CSMC

Written Artefact Profiling Guide

Powder X-ray diffraction (p-XRD)

Stylianos Aspiotis

For powder XRD (p-XRD), a pure, finely ground and homogenized sample (~50-100 mg) is required to determine the various phases comprising the investigated bulk crystalline material. The resulting XRD peaks arise from the constructive interference of the incident monochromatic X-ray beam with each set of lattice planes in a given crystalline sample, whereas the beam is scattered at specific angles. These angles together with the resulting peak intensities are defined by atomic positions within the crystal lattice. Therefore, every mineral has its unique XRD pattern, which can be resembled with its unique fingerprint.

Powder XRD patterns of altered (superficial) and unaltered (bulk) areas of marble-based WA are plotted (after Aspiotis et al., 2021). Cal, Dol and Qz note the Bragg peaks emerging from calcite, dolomite and quartz, respectively.