Raman and SEM‐EDS insights into technological aspects of Medieval and Renaissance ceramics from Southern Italy

• Published in: Journal of Raman spectroscopy 2021-01, Vol.52 (1), p.186-198
• Main Authors: Caggiani, Maria Cristina, Barone, Germana, Ferri, Lavinia, Laviano, Rocco, Mangone, Annarosa, Mazzoleni, Paolo
• Format: Article
• Language: English
• Subjects: Archaeology; Cassiterite; Castles; Ceramics; Coatings; Cobalt; Crystallization; enamel; Enamels; Feldspars; glass; Historic artifacts; Medieval and Renaissence pottery; Phases; pigments; Potassium; Pottery; Questions; Raman spectroscopy; Raw materials; Recycled materials; Scanning electron microscopy; Spectroscopy; Spectrum analysis; Tin; Tin dioxide; tin‐glaze
• ISSN: 0377-0486; 1097-4555
• DOI: 10.1002/jrs.5884

An analytical investigation performed on Southern Italy pottery highlighted the usefulness of Raman spectroscopy to give answers to archaeological questions. It can provide important information concerning the production technology and raw materials constituting the glassy coatings. Raman spectroscopy was supported by Scanning Electron Microscopy coupled with Energy Dispersive X‐ray Spectroscopy (SEM‐EDS) for observations and elemental analysis. The studied samples, ranging from the 13th century lead‐tin‐glazed protomajolica to the 15th –16th enamelled pottery, come from the Castles of Montella and Ariano Irpino (Campania), from the castles of Scicli and Modica and from surveys carried out in Buscemi and Caltagirone (Sicily). Glassy matrices, opacifying agents, colour‐related raw materials and body‐coating interface crystalline phases were investigated. Though the coatings resulted all typically lead‐rich glass types, lumps showing a different Raman profile suggested that at least in one case, the batch was adultered with recycled glass waste. Furthermore, samples coming from Montella, belonging to the three main classes of ceramics defined by archaeological hypothesis, could be grouped according to their cassiterite content. The crystallization of lead–potassium feldspars at the coating‐body interface in a group of samples was ascertained. With regard to the origin of colours, the spectra of blue coatings highlighted phases that can be traced back to the use of Co‐based and Co–As‐based raw materials, while turquoise decorations were found to contain malayaite. Exploiting the characterization of a group of Southern Italy glazed and enamelled pottery, the paper shows the wide range of information that can be extracted by a Raman spectroscopy investigation on this kind of samples. Data concerning the production technology, the main glassy matrices, opacifyers, colouring materials and additional crystalline phases at the body‐glaze interface were collected. Highlights Medieval and renaissance pottery from Southern Italy were analysed. Raman analyses provided unexpected results and answers to archaeological questions. SnO2 Raman bands confirmed the grouping of Montella samples in three classes. Neoformed phases due to reactions during the production processes were discovered. Different cobalt‐based phases were found in the blue enamels.