Multi‐technique investigation of archaeological pottery from Parma (Italy)

Abstract

A ceramic factory with at least three kilns, active from the 14th century until the 17th century, was recently found close to the city walls of Parma (Italy). A series of measurements by different techniques was performed on pottery fragments belonging to the first and last production period. Micro-Raman spectroscopy and scanning electron microscopy-energy dispersive spectroscopy were used to study the glazes and the painting materials, while time-of-flight neutron diffraction and X-ray diffraction were used to characterize the ceramic bodies. The bodies are mainly composed by quartz, diopside, Na-and K-rich alkali feldspars, gehlenite, calcite, and silica-alumina glass; the red coloration is due to hematite. The glazes were obtained using a lead-silica glass, with a fictive temperature of about 600 • C. The main pigments were identified. The ceramics were produced from illitic calcareous clays and annealed in an oxidizing atmosphere at an estimated temperature of 900-1000 • C. Different amounts of magnesium in ceramics of the 14th and 17th century suggest the use of different quarries. The white pigment in the 17th century ceramics, showing the Raman spectrum of nearly pure anatase, is due to a titanium-bearing clay.

Restoration of an Archaeological Ceramic Jar From Mamluk Period (1250–1517A.C.), Al-Fustat, Egypt: An Analytical Study

“…Gehlenite is calcium silicate originating from the thermal transformation of calcareous clays in an oxidizing atmosphere at a temperature ranging from 700-1050 °C. At higher temperatures, it was transformed to another one that was not found in our sample [15]. The presence of gehlenite in addition to the diffuse presence of hematite might suggest the oxidizing atmosphere during ceramic annealing.…”

“…The body contains fine quartz grains in the glassy matrix, in addition to the homogeneity with the appearance of some small gaps, and the shape of grains in terms of coherence and the absence of a separately defined slip layer as the glaze layer is directly applied to the ceramic body. [16] It is noted that the appropriate burning temperature of the ceramic body ranges from 700-1050 °C, where the clay would essentially be an amorphous material with some residual grains of quartz [15]. It may be claimed that the properties of clay differ from one type to another according to the difference in chemical composition.…”

“…For example, during the burial period, the higher level of the ground water could carry the dissolved salts into the pottery pores, leaving them (dissolved salt) behind when the saline water evaporates [14]. The soluble salts are hygroscopic and as the relative humidity rises and falls, the salts repeatedly dissolve and crystallize [15]. …”

Raman Spectroscopy of cultural heritage Materials: Overview of Applications and New Frontiers in Instrumentation, Sampling Modalities, and Data Processing

“…But Raman spectroscopy can also be used to study the mineralogy of the ceramic paste and decoration. The growing use of Raman micro-spectroscopy in this area is related to its spatial resolution, its non-invasive character, the selectivity of signatures, and its convenient implementation, which are particularly attractive for applications to ceramic objects [25,58,109,227]. Studies of the pigments used for ceramic glazes in soft paste, hard paste and majolica ceramics have been the subjects of numerous articles and are extensively reviewed elsewhere [68,84,86,87,90,125,258].…”

Raman spectroscopy in art and archaeology

“…Pottery fragments belonging to the first and last production period of an old ceramic factory, recently found close to the walls of Parma (Italy), active from the fourteenth century until the seventeenth century, were analysed by Bersani et al [27] using micro-Raman spectroscopy and SEM/EDX for the glazes and the painting materials, while time-of-flight neutron diffraction and X-ray diffraction were used to characterise the ceramic bodies. From the different mineral phases identified, authors propose the conditions of ceramic production from illitic calcareous clays and annealed in an oxidising atmosphere at an estimated temperature of 900-1000 • C, without any evidence of a change between the fourteenth and seventeenth century productions.…”