This project plans to study the phenomenon of glass imitations of ornamental objects made of precious stones in Roman times, in order to confirm and expand on existing information, and to analyse antique specimens of pietre dure in their dual capacity as imitated originals and sources of recyclable raw material, thereby opening a window onto the modern era and shedding light on their significance and symbolism.
The study will consider various recently excavated archaeological sites, such as Colonia Celsa, Turiaso, Los Bañales, El Palao, Asturica Augusta and Baelo Claudia, as well as other previously studied sites, and museums with significant holdings, including the National Archaeological Museum in Madrid, Museo de Zaragoza, Museo de Cádiz, Museo de León, Museo de Prehistoria y Arqueología de Cantabria, Museo de Arqueología de Álava and the Gallerie degli Uffizi in Florence.
As a general premise, historiography has assumed that in ancient cultures, traditional products made of precious or prized substances, which only the highest echelons could afford, were imitated, copied or forged in less costly materials, thereby “popularising” (but not necessarily democratising) their consumption.
However, the information at our disposal today allows us to qualify this statement. Such imitations are mentioned in written sources, but they also appear in the archaeological record, and Spain is no exception to the rule, although we are a long way from having a complete catalogue of examples. But while texts mention vessels made largely of precious and ornamental stones (millefiori), these types of stone objects are harder to find in the archaeological record for several reasons, chiefly two: with the spread of Christianity, many were reused as liturgical vessels; and others ended up in the private collections of great patrons over the centuries. This form of “conservation”, even when giving the item a different or modern use, clearly denotes an interest in objects from antiquity and in connecting with that period, as well as the owner’s desire to advertise their good taste and high status. Moreover, those pieces served as models for others made at a later date: some were fashioned from the same material, thereby amplifying the ideological message of the copy, while others were made of more affordable materials, repeating the same skeuomorphic design that had been around since classical antiquity.
Aims and Phases
The project has three main aims:
The first phase entailed compiling and examining documentary sources, locating and contextualising glass and stone items held in museums or found at the dig sites included in the study, and analysing the existing documentation on said items. A database was also designed and created to catalogue the materials, which contains all existing data but has been adapted to new requirements.
The second phase will consist of experimental and analytical work: studying products made of glass, pietre dure and gems; linking original nomenclatures in literary sources to identified archaeological finds; and chemical testing of certain glass pieces at LADICIM (the materials science and engineering laboratory of the Escuela Técnica Superior de Ingenieros de Caminos, Canales y Puertos, Universidad de Cantabria) and SERCAMAT (the materials characterisation service, one of several scientific-technical research services offered by the Universidad de Cantabria). The first step will be a macroscopic analysis to identify the sample with the corresponding type of stone, followed by an SEM+EDS analysis to determine the chemical composition of the glass substrate and pigments used. The second will be to chemically analyse the samples using X-ray fluorescence (XRF) spectrometry. This method, which complements SEM+EDS, is particularly useful for analysing glass because it provides quantitative results, expressing the elements present as oxides, making it easy to directly compare them with the elements reported in most scientific literature. The ultimate purpose is to identify the materials used, understand the production method and, if possible, identify the place of origin.
Precious and ornamental stones will be identified visually, given the size of the objects, their importance as exhibits, the fact that most are coloured rocks, and the difficulty of taking samples to run destructive tests. If the gems can be removed for analysis, we will use non-destructive instruments such as a standard refractometer, polariscope, UV lamp and even SEM/EDS.
During the third phase, with regard to antiquity, researchers will focus on the terminology used in sources, the systematisation of imitated and imitating items, and glass production (technology and composition) in order to obtain social and financial information about the users of the (imitated and imitating) products and, if possible, the workers who made them. They will also conduct regional analyses, combining the data obtained from this project with the results of the previous one, and considering all this information as part of the larger phenomenon of imitations in the ancient world in general and the Roman period in particular, which will undoubtedly increase our knowledge of the imitation process. With regard to the modern era, researchers will concentrate on identifying the forms and materials of pietre dure vessels that were made in antiquity and later reused, and tracing those forms in antique items made of other materials (metal, pottery and or/glass), in their possible ideological, symbolic or status-related purposes, and in modern glass imitations of antique models.
The participants also intend to hold a scientific conference at the end of the project, where they can present and compare their conclusions with other groups in Spain and abroad who are investigating similar topics (imitations of different material productions in different periods), and produce a publication to share their findings with the scientific and international community.