Multi‐technique characterization of glass mosaic tesserae from Villa di Teodorico in Galeata (Italy). (15th June 2021)

• Record Type: Journal Article
• Authors: Bersani, Danilo; Saviane, Luciana; Morigi, Alessia; Mantovani, Luciana; Aceto, Maurizio; Fornasini, Laura
• Other Names: Kiefer Wolfgang guestEditor.; Colomban Philippe guestEditor.; Edwards Howell G. M. guestEditor.
• Is Part Of: Journal of Raman spectroscopy. Volume 52:Number 12(2021)
• Page Start: 2234
• Page End: 2245
• Publication Date: 2021-06-15
• Subjects: FORS -- glass mosaics -- micro‐Raman spectroscopy -- SEM‐EDS -- XRPD; Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.6180
• Languages: English
• ISSNs: 0377-0486

Abstract

Abstract: Several glass mosaic tesserae were found during the archeological excavations at the Villa di Teodorico in Galeata (Forlì‐Cesena, Emilia Romagna, Italy), dated to early sixth century AD. This work reports the results of an archeometrical investigation realized through a multi‐technique approach on 16 tesserae . The aims of the study were the determination of the glass composition, the characterization of coloring and opacifying agents, and the definition of the technological processes involved. The glass matrix and the dispersed crystallites were characterized in detail through micro‐Raman spectroscopy, field emission scanning electron microscopy with energy‐dispersive X‐ray spectroscopy, and X‐ray powder diffraction analyses. Micro‐Raman spectroscopy was proven to be very effective in the analysis of complex objects, providing information on the structure and composition of the glass and on the nature of the opacifying agents and the crystalline colorants. UV–visible–NIR diffuse reflectance spectrophotometry with optic fibers was helpful to identify the metal ions used as chromophores. The different hues were obtained by means of dispersed ions as well as crystalline compounds and metal nanoparticles. A large variety of opacifying agents was detected. Results were compared with data of contemporary mosaics within the same geographical area. Abstract : This work reports the results of an archeometrical investigation realized through a multi‐technique approach on 16 tesserae found during the archeological excavations at the Villa di Teodorico in Galeata (Forlì‐Cesena, Emilia Romagna, Italy), dated to early sixth century AD. Raw materials, composition, and structure of glassy matrix and crystalline inclusions acting as colorants and opacifiers have been identified. An evolution of the production technology respect to mosaic tiles coming from slightly older buildings of the same region is shown.