Characterization of clays and the technology of Roman ceramics production

Abstract

The recent discovery of a Roman ceramics manufacturing workshop at Montelabate (Perugia, Italy), in use from the first century BC until the late-fourth to fifth centuries AD, offers a unique opportunity to study the technical processes for producing Roman amphorae. Ancient and modern clays were sampled and analysed; they do not differ significantly, supporting the hypothesis of the exploitation of the rich local clay source that allowed a continuity of production. Characterization of the clays was performed using geotechnical methods (Atterberg limits and size distribution) and by thermogravimetric and differential thermogravimetric analysis, Fourier-transform infrared spectroscopy, X-ray diffraction and X-ray fluorescence analyses. The material was suitable for pottery making with the addition of calcite and quartz sand temper. Production waste and discarded materials as well as good-quality products were also analysed with the same methodology. It is therefore possible to reconstruct the ancient technology by defining the recipe for the production of the amphorae and their firing temperature on the basis of the decomposition of clay materials and the presence of newly formed minerals.

Compositional characterization of Etruscan earthen architecture and ceramic production

“…The XRD clay fraction amount differs from geotechnical analyses that classify a soil only on the basis of granulometry, without considering the microstructure of the material or its chemical composition (Ceccarelli et al . 2018). For instance, different amounts of clay minerals in sample ER02 (15%) indicates that a lower degree of water content and plasticity was necessary for its use.…”

“…The analysis of the hilltop settlement raw clayey material and the results of the compositional characterization of soils in the valley of Montelabate (Ceccarelli et al . 2018) allow the exploration of wider issues such as the technology of raw materials in building construction compared with their use for ceramic production, and the exploitation of resources in the Etruscan world, pivoting around the Upper Tiber Valley.…”

Archaeometric Investigations on Archaeological Findings from Palazzo Corsini Alla Lungara (Rome)

“…Numerous clay materials with a variety of colours and grain sizes were discovered during the archaeological excavation, some of which show evidence of combustion or thermal transformation that are commonly referred to as "burned clays." These clays were most likely part of the structural works discovered during the excavation [20]. The materials analysed are from the quadrants A (C1A, C1B, C2, C3, and SNZ1) and B (GRU1 and PIG1).…”