Diffraction-based techniques are fundamental tools for the characterization and understanding of materials of different nature, including those relevant to cultural heritage. Both conservation science and archaeometry may extensively profit from the information provided by diffraction techniques. The various methods and techniques of single-crystal and powder diffraction as applied to cultural heritage materials are briefly described with reference to specific examples, focusing on the extracted information in terms of (1) phase identification and quantification of crystalline compounds and complex polyphasic mixtures, (2) the texture and orientation of the crystalline phases, (3) the atomic and molecular structure of the phases involved, and (4) the physical microstructural state of the material in terms of crystallite size and accumulated strain. This paper presents a review of X-ray techniques used in art and archaeology and their applications as a non-destructive research tool in examining artistic and ancient objects. XRD is a standard procedure that provides information about the manufacturing process and condition of objects without physical contact, as well as insights into material composition and crystalline structure, making it widely used by archaeologists, curators, and conservators. The present paper aims to discuss the contribution of X-ray diffraction to cultural heritage and archaeology studies, based on personal experiences and those of other colleagues with various crystalline and non-crystalline materials. For this reason, the paper presents only a selection of cases identified by X-ray diffraction in cultural heritage conservation studies. It should be noted that X-ray diffraction plays a critical role in the analysis and characterization of these diverse materials. Another important goal of this work is to encourage in-depth studies on the use of X-ray techniques in the study of historical, archaeological, and artistic materials.
The Sofalin Mound is located north of the city of Pishva, on natural hills formed by early Holocene deposits (alluvial sediments older than 4,000 years). Systematic and continuous excavations at the Sofalin Mound have been carried out over the past several years in seven seasons as part of broader archaeological investigations in the Varamin–Pishva Plain. Cultural materials recovered from the Sofalin Mound in the north-central Iranian Plateau have significantly enhanced our understanding of the proto-literate period, dated between 3500 and 2800 BCE, within the cultural sphere of the north-central plateau of Iran. During the sixth and seventh excavation seasons at the Sofalin site, architectural spaces were uncovered in Trench 20. These spaces were documented as featuring cobblestone floors, mudbrick platforms, and rectilinear architectural layouts. Based on ceramic assemblages (plain and painted), clay sealings, and fragmented clay tablets, occupation during different phases of theEarly Elamite cultural period was identified. This research focuses on the technical and laboratory investigation of Early Elamite mudbrick architectural remains from the Sofalin Mound using X-ray diffraction (XRD) analysis, complemented by chemical studies aimed at proposing appropriate conservation strategies. The primary objective of this study is to achieve a semi-quantitative structural characterization of mudbricks from this period in order to enhance our understanding of their mineralogical composition. Such knowledge contributes to the development of effective conservation approaches for the Sofalin Mound as well as other contemporaneous mudbrick archaeological sites.
