Pigments and Plasters Discovered in the House of Diana (Cosa,Grosseto, Italy): An Integrated Study Between Art History,Archaeology and Scientific Analyses*

The pigments and the plasters of the Roman frescoes discovered at the House of Diana (Cosa, Grosseto, Italy) were analysed using non‐destructive and destructive mineralogical and chemical techniques. The characterization of both pigments and plasters was performed through optical microscopy, scanning electron microscopy and electron microprobe analysis. The pigments were identified by Raman spectroscopy and submitted to stable isotope analysis. The results were integrated with the archaeological data in order to determine and reconstruct the provenance, trade patterns and the employment of the raw materials used for the elaboration of the frescoes.     

ACCESSORY MINERALS AS TRACERS IN THE PROVENANCING OF ARCHAEOLOGICAL MARBLES,USED IN COMBINATION WITH ISOTOPIC AND PETROGRAPHIC DATA*

Thirty‐eight archaeological marbles (Roman and medieval) from Modena and Reggio Emilia (northern Italy) were provenanced using the accessory minerals as tracers and the results were compared with those inferred for the same artefacts using isotope composition and MGS (maximum grain size of calcite grains). The number of inferred possible sources is generally lower when using the mineralogical method, which therefore seems to be suited to marble provenancing.     

THE SECTILIA PANELS OF FARAGOLA (ASCOLI SATRIANO,SOUTHERN ITALY): A MULTI‐ANALYTICAL STUDY OF THE GREEN,MARBLED (GREEN AND YELLOW), BLUE AND BLACKISH GLASS SLABS

Analyses at the Cu–K, Fe–K and Mn–K edge were performed to study the green, marbled (green and yellow), blue and blackish (deep greyish olive green) glass slabs decorating three sectilia panels from the archaeological site of Faragola. Results indicate that all slabs were made by mixing siliceous sand with natron, sometimes probably mixed with small percentages of plant ash. Cu²⁺ and Pb antimonates should be responsible for the opaque green colours. The dark green and yellow portions of the marbled slabs are respectively comparable to the slabs comprising only one of these colours. Cu²⁺ together with Ca antimonates probably produced light blue slabs, whereas cobalt was used to produce dark blue slabs. We consider it possible that the abundance ratio of Fe²⁺/Fe³⁺ and the complex Fe³⁺S^2? would have an effect on the blackish slabs. The contribution of Mn cannot be ascertained even if it could have played a role in darkening glass colour. The comparison between the chemical composition of Faragola samples and several glass reference groups provided no conclusive evidence of provenance; whereas, the presence of a secondary local workshop can be hypothesized.     

SCIENTIFIC ANALYSIS OF SEVENTH‐CENTURY GLASS FRAGMENTS FROM THE CRYPTA BALBI IN ROME*

Inductively coupled plasma emission spectroscopy, reflectance spectroscopy and X‐ray diffraction were used to study seventh‐century AD glass fragments from the Crypta Balbi in Rome. All the samples were found to be silica‐soda‐lime glasses. Iron determines the colour of blue‐green, green and yellow‐green transparent glasses; chemical composition suggests deliberate addition of iron and/or manganese in about half the samples. Copper was found as the main colourant in red, pale blue and blue‐green opaque fragments; elemental copper acts as an opacifier in red glass, and calcium antimonate in white, pale blue and blue‐green glasses. Detection of antimony in transparent fragments suggests recycling of opaque mosaic tesserae.     

THE OPAQUE RED GLASS OF CELTIC ENAMELS FROM CONTINENTAL EUROPE

Opaque red glass was used in the Celtic world for enamels and inlays. Forty artefacts, of various dates and found in various places, have been sampled and studied. They all belong to the same type, a soda-lime-silica high lead glass coloured by crystals of cuprous oxide. There is only one subgroup: glass lumps from the Mont-Beuvray oppidum contain manganese, less iron, and less lead. This change could be the result of Roman influence. Although most of these glasses form a surprisingly homogeneous group, no conclusions as to their origin can be inferred from our present knowledge.     

The production and technology of glazed ceramics from the middle ages,found in the saepinum territory (Italy): a multimethodic approach*

A collection of ceramics from the Middle Ages found in Altilia and Terravecchia (the Saepinum area, Campobasso, Italy) were characterized by using different mineralogical analyses to investigate their provenance and production techniques. The body ceramic was investigated using Rietveld phase analysis of X‐ray powder diffraction patterns, X‐ray fluorescence spectrometry and scanning electron microscopy. The chemical compositions of the coatings were measured by scanning electron microscopy and their mineralogical compositions were determined using a particular technique of X‐ray small‐angle scattering (SAS) optimized for studies of thin films. Moreover, the material used for decoration was studied using micro‐Raman spectroscopy. The archaeometric results confirmed the distinction into two different ceramic classes, already individuated from archaeological analysis: the Altilia objects belong to the protomajolica class, whereas the objects from Terravecchia are RMR (ramina‐manganese‐red) ceramics. A comparison between the chemical and mineralogical compositions of good‐quality ceramic objects and those of waste products indicated local production of the ceramics. A sharp distinction was found in the chemical composition of the coatings: the Altilia products have tin‐opacified lead glazes, while the Terravecchia ones have transparent high‐lead glazes. Among the Altilia products, the unsuccessful process that produced a large quantity of discarded materials was attributed to the high lead content of the glazes. In fact, the principal advantage of the high lead content was to make the preparation and application of the glaze suspension easier, but the risk of reduction of lead oxide to metallic lead was greatly increased. Using micro‐Raman spectroscopy, the following minerals were identified as pigments: pyrolusite for the dark colour, malachite for green, lepidocrocite for yellow and hematite for red.     

GLASS CORROSION ACROSS THE ALPS: A SURFACE STUDY OF CHEMICAL CORROSION OF GLASSES FOUND IN MARINE AND GROUND ENVIRONMENTS*

Ancient glasses deriving from differing environments (marine and ground) and areas (Mediterranean and Continental) have been investigated to understand their weathering processes. Although the glass technologies, developed in various ways, and the differing compositions of the glasses from the two areas, have generated differing durabilities, the weathering features of both typologies of glass are identical. Therefore, the corrosion phenomena are due to the action of water, and they are not related to the sample microclimate. Data have been collected using optical microscopy, RGA and surface analysis techniques: XPS, ESEM and SIMS.     

CHARACTERIZATION OF PLASTERS AND MORTARS AS A TOOL IN ARCHAEOLOGICAL STUDIES: THE CASE OF LARDIRAGO CASTLE IN PAVIA,NORTHERN ITALY*

Plasters and mortars from Lardirago Castle (Pavia, northern Italy) have been characterized by means of petrographical and chemical analyses in order to achieve technical and historical evidence of material production. The study focused on the oldest nucleus of the structure, where hidden plastered masonry has been discovered recently. Textural and compositional data of the binder and the aggregate fractions were collected by means of optical microscopy and electron microscopy coupled with microanalysis. These data permit the identification of building materials with similar technical and compositional characteristics, which can be related to different building phases.     

THE SUPPLY OF CAMPANIAN‐MADE SIGILLATA TO THE CITY OF POMPEII

Pompeii is an important temporal reference in the study of Roman ceramics, yet until now the origins of red slip tableware or sigillata found in the city have largely been classified by visual evaluations of the pottery. This investigation employs petrographic and elemental analyses to establish the provenance of sigillata found in two pre–ad 79 contexts of Pompeii. In contrast to previous studies, the results suggest that pottery workshops in the vicinity of Somma‐Vesuvius played a vital role in the supply of sigillata to the city.