1,721,064 research outputs found
Pigments-Arsenic-based yellows and reds
No full textThis review offers an update on arsenic-bearing minerals and pigments with the aim of serving as a guide for the study of Cultural Heritage materials in which these materials can be found.The different As-bearing mineral phases (realgar, pararealgar, orpiment, anorpiment, alacranite, dimorphite, bonazziite, uzonite, wakabayashilite, duranusite, arsenolite and claudetite) and some of their light-induced products are examined The occurrence of As-sulfides and their trade, use, alteration and degradation are also reviewed. Finally, the analytical techniques commonly used for the identification of arsenic-containing pigments are discussed. The manuscript concludes with a good-practice guide and a summary of key concepts for use by those working in the field of cultural heritage
La diffusione dei bolli laterizi "urbani" nell'Etruria romana: rapporti tra produzione "urbana" e "municipale"
No full textIl lavoro esposto in queste pagine offre un sunto preliminare e parziale della ricerca in corso sui laterizi bollati dell’Etruria romana. La ricerca ha coperto l’intero territorio di riferimento tramite lo spoglio bibliografico delle fonti mentre la schedatura autoptica ha raggiunto i confini della Toscana odierna, varcati esclusivamente per lo studio dei materiali lunensi .
La differenza numerica e tipologica riscontrata in Toscana tra materiale edito ed inedito motiva l’omissione delle attestazioni umbre e laziali da questo studio sulle produzioni laterizie dell’Etruria romana. L’irreperibilità di numerose produzioni edite e la frequente omissione delle quantificazioni e delle trascrizioni nei testi rendono inoltre preferibile lo studio dei tipi epigrafici piuttosto che del loro numero di attestazioni.
La distinzione tra produzioni “municipali” ed “urbane” utilizzata per l’esposizione dei dati è convenzionale ed innegabilmente antiquata. I due termini vengono qui utilizzati per distinguere le produzioni laterizie verosimilmente toscane (“produzioni municipali”) da quelle altrettanto verosimilmente urbane e tiberine (“produzioni urbane”). La forzatura che si esercita nell’applicare questa terminologia deriva in gran parte dalla mancanza di informazioni sui luoghi della produzione ed in minor misura dall’estensione anacronistica della “condizione municipale” a produzioni cronologicamente tarde. Si tiene quindi a precisare che i due termini verranno utilizzati non senza incertezze ma con l’indubbio vantaggio di poter proporre alcune schematizzazioni dei dati distributivi.
La mancanza di informazioni riguardanti i luoghi di produzione e l’esistenza di numerose collezioni private complicano oltremodo la realizzazione di un quadro complessivo accurato e sufficientemente articolato. Da una parte, infatti, l’area descritta dalla distribuzione degli esemplari non corrisponde necessariamente all’area di produzione , dall’altra parte i materiali acquisiti attraverso collezioni private non conservano le informazioni riguardanti il luogo di rinvenimento. Le collezioni di laterizi bollati conservate presso il Museo dell’Accademia Etrusca di Cortona, il Museo Guarnacci di Volterra, il Museo Civico di Fiesole ed il Museo Civico di Chianciano offrono un repertorio “urbano”, privo di qualsiasi indicazione circa i luoghi di rinvenimento degli esemplari.
Quanto alle datazioni proposte, la Cronologia delle figlinae doliari urbane ha costituito lo strumento per la datazione delle produzioni “urbane” in Toscana mentre, una “cronologia delle produzioni doliari municipali” è tuttora in corso di elaborazione e precisazione. Alcuni esemplari “municipali” vengono datati con precisione dai loro Editori, la maggior parte di essi invece gode di una datazione piuttosto ampia e suscettibile di modifiche.
Da ultimo, occorre sottolineare che oggetto della presente ricerca sono le produzioni laterizie bollate e, pertanto, le schematizzazioni proposte non sono immediatamente applicabili alla produzione laterizia nel suo complesso
Black gloss pottery: production sites and technology in northern etruria. Part I: provenance studies
No full textThe object of the present study is an assemblage of 149 black gloss pottery samples found in northern Etruria (Tuscany, Italy), at Arezzo, Volterra, Chiusi and Populonia. Complete chemical analyses have been performed for the whole set of samples, whereas mineralogical characterization has been provided for most of the Volterra, Chiusi and Populania samples. The Chiusi-Marcianella production site has been the further object of a detailed study aimed at the creation of a complete reference group. Moreover, several trade routes have been reconstructed, shedding light on the import and export of these ceramics from inland Etruria to the coast and vice versa
The 'Madonna and Child Enthroned with Saints' of Ambrogio Lorenzetti in the St. Augustine Church (Siena, Italy): Raman microspectroscopy and SEM-EDS characterisation of the pigments
No full textRaman microspectroscopy combined with scanning electron microscopy was applied to the investigation of the Madonna and Child Enthroned with Saints of Ambrogio Lorenzetti (early 14th century; St. Augustine church, Siena, Italy). A detailed investigation of both the materials used for the wall painting and the alteration products was provided in order to increase the level of accessibility of this masterpiece and to stimulate its restoration. The results showed that the pigments used for this wall painting were those widely used by medieval painters: chalk white, white lead, yellow ochre, red ochre, red lead, cinnabar, Siena earth, green earth, verdigris, azurite, and carbon black. Gilded tin foil has been further used for the decoration of the haloes. The alteration products mainly consist of Ca sulfates and Ca oxalates. Fungal spores were further observed in correspondence to the application of lead-based pigments. © 2014, Springer-Verlag Berlin Heidelberg
Ceramic technology: how to characterize terra sigillata ware
No full textAs part of the Topical Collection on the archaeometric study of ceramics, this paper focuses on terra sigillata ware. The main aims are to provide a review on the state of the art of the studies and to provide a guide to the most suitable analytical techniques. The text is divided into four main parts: (1) a brief archaeological introduction on the ancient production of terra sigillata; (2) a summary of the archaeometric studies carried out to date; (3) a reasoned list of the most suitable techniques for the investigation of the ceramic body and (4) an in-depth discussion on the most effective techniques for the study of the coating. The application of both destructive and non-destructive techniques is critically evaluated as well as the advantages and disadvantages provided by the different instrumentation, in terms of sample preparations and expected results
Application of the Rietveld method for the investigation of mortars: a case study on the archaeological site of Thamusida (Morocco)
No full textThis study presents a multi-technique approach to the investigations of mortars, involving the application of the Rietveld method. The quantitative mineralogical analysis of samples was aimed at (1) verifying its significance in relation to results obtained through other techniques and (2) evaluating its potential in mortars characterisation.
Six type of mortars used in the Roman settlement of Thamusida (50 km north of Rabat, Morocco) were investigated through X-ray powder-diffraction and Rietveld refinement, optical microscopy, image analysis, scanning electron microscopy, electron microprobe analysis, X-ray fluorescence (XRF) and combined differential thermal, and thermo-gravimetric analysis (DT-TGA).
All the adopted techniques yielded unique results and complementary data; however, the Rietveld method can actually Substitute thermal analysis accurately. CaO oxide contents obtained by DT/TGA and Rietveld are in good agreement, but both were only partly comparable to XRF results. In our case, XRF and Rietveld results diverge when binders contain more than 67 wt.% CaO. The discrepancies can mainly be ascribed to the presence of amorphous material and to the obtainable accuracy by QPA-Rietveld method; conversely, the nonstoichiometry of phases does not affect our results, because phases with variable compositions are present in small amounts.
Results further showed that the adopted methods were suitable for mortar characterisation. All studied mortars (1) have weak hydraulic properties; (2) employed binders characterised by highly variable CaO contents and by significant amounts of SiO(2); (3) used coarse to fine quartz-carbonate-rich sands as the aggregate; and (4) selectively mixed 2 or 3 parts of aggregate with I part of binder, depending on the destination of the mortar
Old recipes, new strategies: Paleoenvironment, georesources, building materials, and trade networks in Roman Tuscany (Italy)
No full text© 2020 Wiley Periodicals, Inc. The Grosseto plain has undergone extensive morphological changes. The shoreline progression has been taking place during the last millennium and has deeply affected settlement, infrastructural, and socioeconomic dynamics. Consequently, this study aims to (a) localize the raw materials exploited during the Roman period for building materials production, (b) reconstruct the production technology, and (c) provide a meaningful reconstruction of the commercial dynamics between local “municipal” productions and “urban” imports. The chemical, mineralogical, and petrographic investigations performed on 34 stamped bricks from the Roman territories of Vetulonia, Rusellae, Heba (Aia Nova), and Saturnia supported the following major achievements: (a) Most of the Rusellan producers used the continental deposits outcropping along the Ombrone River while a few of them exploited the coastal or marine deposits. Aia Nova and Saturnia producers used the Zanclean marine deposits. (b) Brick-making technology involved very little or no preparation of the paste and firing temperatures ranging between ~650°C and 900°C. Calcite temper was found in Rusellan bricks while decantation was hypothesized for Saturnia bricks only. (c) Commercial dynamics changed abruptly after the the mid 1st century AD when local productions, run by local aristocracies, started declining in favor of urban imports, until being completely supplanted during the Trajan age
Roman bronze artefacts from Thamusida (Morocco): Chemical and phase analyses
No full textTwenty-six objects (1st to the 3rd century AD) found at the archaeological site of Thamusida (Morocco), which is a military settlement between the 1st and the 3rd century AD, have been investigated by means of portable X-ray fluorescence and time of flight-neutron diffraction. The combination of element-sensitive X-ray fluorescence and structure-sensitive neutron diffraction yields, in a totally non-destructive way, the necessary information to discriminate the copper alloy from corrosion and alteration layers. Results allowed dividing the repertory into five groups: (a) unalloyed copper, (b) binary alloys made of Cu and Sn, frequently leaded; (c) unleaded binary alloys made of Cu and Zn; (d) ternary alloys made of Cu, Sn and Zn, both leaded and unleaded; (e) quaternary alloys made of Cu, Sn, Zn and As. The choice of alloy is heterogeneous, mainly depending on availability and costs of raw and/or scrap materials and on technological constraints. Interestingly, the reconstruction obtained for Thamusida could either anticipate the important change in the Roman use of copper alloys generally referred as 'zinc decline', or more likely, indicate that brass never conspicuously entered the local metal-working activities of this military site
The early Roman pottery kilns in the ager Rusellanus (southern Tuscany, Italy) and their products
No full textThis archaeometric research examined the structural elements of the three kilns found in the plain below the archaeological site of Rusellae, the ceramics found within this artisans' quarter and the clayey materials on which the workshops were built. Twenty-one samples were investigated by bulk chemical and mineralogical analyses (ICP-MS, ICP-AES and XRD) and mineralogical-petrographic analyses on thin sections (optical microscopy and scanning electron microscopy). The results allowed the characterisation of the production group to be obtained. Both carbonatic and non-carbonatic clayey materials were used to make common-ware ceramics and, above all, building materials such as bricks and tiles. The production technology varied from accurately to poorly worked pastes, fired from low (about 800 degrees C) to very high temperatures (above 1100 degrees C). The compositional comparison with data previously obtained on stamped bricks and neighbouring clayey materials suggested a correlation with the producer/s known by the stamps SEX CLEMENT/PROBI and PROBI. Furthermore, the variety of raw materials used in the manufacture and product diversification also let speculate that the production site welcomed various artisans and products for the final firing
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