The technology of copper-based red glass sectilia from the 2nd century ad lucius verus villa in rome

PD/BD/135053/2017This work aimed to investigate the origin of different red hues of Roman copper-based red opaque glass sectilia, to shed light on the production technology behind them. This objective was achieved by the depth study of the samples of glass sectilia, which decorated the villa of co-Emperor Lucius Verus (161–169 AD). These were selected for analysis due to their abundance, the certainty of their date and of their different red and orange hues. Using OM (optical microscopy), colourimetry and FORS (fibre optical reflectance spectroscopy) spectroscopy, four red and four orange hues were individuated. A set of representative samples for each hue was analysed by EPMA (electron probe microanalyses) to detect any correlation between colour and chemical composition. Crystalline phases were investigated through high-resolution FEG–SEM (field emission gun scanning electron microscope), µRaman spectroscopy and XRD, for the identification of colouring and opacifying agents and to understand how the different hues are affected by their shape, concentration and dimension. Sub-micrometric particles of metallic copper and cuprite crystals were identified as both the colouring and opacifying agents. These were not present in the same samples and were manufactured by two distinct colouring techniques, corresponding to two different glass chemical compositions. The size and the number of the colouring particles were the main factors that distinguished one hue from another. Although produced through different colouring techniques, some red samples appeared to be very similar to each other. These data enrich a period of the Roman age through some analyses and allow the identification of the type, as well as some of the production conditions of opaque red glass produced during 2nd century AD, which could be considered to be a period of transition from one technology to another.publishersversionpublishe

Nanotechnology in Roman Opaque Red Glass from the 2nd Century AD. Archaeometric Investigation in Red Sectilia from the Decoration of the Lucius Verus Villa in Rome

PD/BD/135053/2017 UID/EAT/00729/2019This work aims to characterise the chemical composition of Roman opaque red glass sectilia dated to the 2nd century A.D and to shed light on Roman glassmaking production of different shades of red, from red to reddish-brown. Due to the lack of technical historical sources for this period many questions about technological aspects still remain. In this project a multi-disciplinary approach is in progress to investigate the red glass sectilia with several red hues from the Imperial Villa of Lucius Verus (161–169 A.D.) in Rome. First, colorimetric measurements were taken to identify the various red hues. The second step was chemical characterization of the samples and the identification of crystalline colouring phases. Particle Induced X-Ray Emission (PIXE) analysis was used to investigate the chemical composition of these glass samples, while the crystalline phases were identified by Raman Spectroscopy and Scanning Electrons Microscope with Energy Dispersive X-ray Spectrometry (SEM-EDS). Using SEM-EDS nanoparticles were detected as a colouring agent, the chemical composition and the morphology of which has been studied in depth. This information has been compared with the colorimetric analysis to establish any correlation with the different colour hues.publishersversionpublishe

Glass mosaic tesserae from the 5th-6th century baptistery of San Giovanni alle Fonti, Milan, Italy. Analytical investigations

peer reviewe

Produrre tessere d’oro: bordi di piastra, ricettari, analisi archeometriche

peer reviewe

Frammenti della decorazione parietale del mausoleo imperiale di Milano (IV sec.): i materiali e la loro caratterizzazione

peer reviewe

Caratterizzazione chimico-fisica di mattoni gotici veneziani

The aim of this experimental work was determine the characteristic features of Venetian Gothic bricks, in order to create an initial database for the city of Venice, and improve our knowledge of this class of materials, for the conservation of the walls of Gothic buildings and the dating of architectural surfaces. The study was extended to bricks found in dated archaeological sites of the town and of the Venetian lagoon. A total of 34 samples was subjected to mineralogical-petrographic, chemical and physical analysis (oM, XRD, SEM + EDS, XRF, MI) to get a initial overview about these Venetian bricks. The results identified some groups of samples sharing the same source materials and, probabily, also the same manufacturing technology. The study showed that this grouping does not depend on the origin of the bricks, rather on their dating, as di-mostrated by comparison with data related to more ancient Venetian bricks

Glass and gold: Analyses of 4th–12th centuries Levantine mosaic tesserae. A contribution to technological and chronological knowledge

International audienc

Chemical analysis of 17th century Millefiori glasses excavated in the Monastery of Sta. Clara-a-Velha, Portugal: comparison with Venetian and façon-de-Venise production

a b s t r a c t A set of ten Millefiori glass fragments dating from the 17th century, originated from archaeological excavations carried out at the Monastery of Sta. Clara-a-Velha (Coimbra, Portugal), were characterized by X-ray electron probe microanalysis (EPMA), Raman microscopy and UVeVisible absorption spectroscopy. All glasses are of soda-lime-silica type. The use of coastal plant ash is suggested by the relatively high content of MgO, K 2 O and P 2 O 5 , as well as by the presence of chlorine. Tin oxide or calcium antimonate were the opacifiers used in the opaque glasses, cobalt in the blue glasses, copper in the turquoise glasses, iron in the yellow and greenish glasses, and iron and copper were found in the opaque red and aventurine glasses. Based on the concentrations of alumina and silica four different sources of silica were identified, allowing the classification of the glasses into the following compositional groups: low alumina (<2 wt%), which includes a sub-group of cristallo samples with SiO 2 > 70 wt%, medium alumina (2e3 wt %), high alumina (3e6 wt%) and very high alumina (>6 wt%). Comparison with genuine Venetian and façon-de-Venise compositions showed that two fragments are of Venetian production, one of Venetian or Spanish production and the remaining are of unknown provenance. In two fragments the glass of the decoration is probably Venetian or Spanish but the glass used in the body is also of unknown provenance

Indagini sui processi di dissoluzione di infusi alluminosi nel vetro cavo industriale

Nel presente lavoro si è cercato di approfondire lo studio degli injùsi alluminosi, un tipo di difetto di produzione di vetro cavo industriale piuttosto comune e al tempo stesso pericoloso. Gli infusi analizzati sono dovuti principalmente all'utilizzo di miscele vetrificabili accidentalmente contaminate da granuli di bauxite, a granuli di origine ceramica apportati dall'uso di rottame da riciclo, a refrattari e a malte impiegate nelle riparazioni. I campioni sono stati analizzati tramite microscopia elettronica a scansione (SEM) per l'individuazione delle caratteristiche microstrutturali e microanalisi ai raggi X a dispersione d'energia EDS, per determinare le composizioni chimiche delle diverse fasi (fasi cristalline primarie e secondarie e zonature vetrose). Particolare attenzione è stata riposta nell'analisi delle reazioni che hanno luogo tra gli infusi alluminosi ed il vetro fuso ed i meccanismi di diffusione che governano i processi di dissoluzione dell'inclusione. A tal fine, sono stati anche eseguiti dei test di corrosione in laboratorio, per approfondire il meccanismo di dissoluzione di materiale ceramico e refrattario a contatto con un vetro cristallino. Sulla base di dati microtessiturali e microanalitici raccolti, si è potuto correlare le caratteristiche di infusi alluminosi alle diverse tipologie d'inquinanti. L'inquinante bauxitico dà luogo ad infusi con contorni molto lobati, caratterizzati da fasi globulari nefeliniche ed una intensa zonatura composizionale. Gli infusi di origine ceramica si presentano invece molto trasformati e circondati da un'estesa zonatura composizionale. Anche gli infusi da refrattario risultano molto trasformati con residue fasi cristalline secondarie. Infrne, gli infusi da malta si presentano compatti, con un'estesa zonatura composizionale e fasi secondarie nefeliniche in prossimità delle lobature. Le analisi hanno permesso di ricostruire la possibile evoluzione del difetto da materiale cristallino originario fino alla completa trasformazione in un nodulo vetroso. Parametri come il tempo di permanenza nel forno, la cinetica delle reazioni e la composizione e natura del materiale alluminoso si sono rivelati critici per tale evoluzione. Le prove di laboratorio hanno per- messo di ipotizzare che anche piccole percentuali di potassio siano fattori catalitici nei processi di dissoluzione degli infusi. E' stato inoltre possibile dimostrare come indagini di tipo chimico-mineralogico accuratamente condotte risultino estrema- mente importanti per una completa caratterizzazione dei difetti. Aluminous stones are a quite common, dangerous defect in container glass. The stones analysed in the present work are due to the use ofinvoluntarily contaminated batches containing bauxite grains, ceramic grains introduced by recycled cullet, or grains coming from refractories and mortars used in repairs. The samples were analysed by SEM and EDS-X ray microanalysis to determine microstructural characteristics and the chemical composition of the different phases. In arder to understand the reactions occurring between the aluminous stones and the molten glass, and the diffùsion mechanisms governing the dissolution process, laboratory corrosion tests were carried out on ceramic and refractory materials in contact with a crystal glass. The microtextural and microanalytical data obtained allowed a correlation to be established between the characteristics of the examined stones and the different IJIpes of contaminant. The results showed that the reaction kinetics greatly affect the transformation process of these hetorogenities. The dwelling rime in the furnace, the reaction kinetics, and the composition and nature of the aluminous material, are criticai parameters affecting the transformation of the defect from the originai crystalline material into a completely glassy knot. The laboratory tests also suggested that even small percents of potassium have a catalytic effect on the stone dissolution processo Properly performed chemical-mineralogical investigations were shown to be extremely useful far an exhaustive characterization of these defects