Raman analysis of ninth-century Iraqi stuccoes from Samarra

Six ninth-century stucco fragments from Samarra, Iraq, and now part of the Victoria and Albert Museum collections, were analysed non-destructively and in situ in the Museum by Raman microscopy in order to determine the identities of the pigments thereon. Carbon black, haematite, gypsum, indigo, lazurite, lead white, orpiment, pararealgar, red lead, vermilion and the As₄S₄ χ-phase were detected. The detection of several arsenic-containing pigments (orpiment, pararealgar and the As₄S₄ χ-phase), known to be poisonous and carcinogenic, has prompted strict health and safety protocols to be used when the objects are handled by museum staff or displayed in the galleries. This scientific study is the first to be carried out on any of the Samarra finds.     

Investigating the presence of ancient absorbed organic residues in groundstone using GC–MS and other analytical techniques: a residue study of several prehistoric milling tools from central California

Analysis of absorbed organic molecules in groundstone could provide a valuable means to study resource use and processing in antiquity. The following study analyzed extracts from the surfaces of several central California milling tools to assess whether organic residues remained from prehistoric resource processing. It also sought to determine which source identification methods are likely to be successful at providing information about the type, or even the specific identify, of resources that were processed. Lipids (primarily fatty acids) were analyzed using GC–MS and the presence of phenolic compounds was assessed with UV-Vis spectroscopy. Milling surfaces were compared to previously broken surfaces from the same tool with the assumption that both surfaces had been exposed to similar post-depositional conditions. Results supported the presence of ancient residues in milling tools. A higher concentration of fatty acids was recovered from milling surfaces than paired broken surfaces. Furthermore, measurable amounts of azelaic acid (an oxidation product of some unsaturated fatty acids) were present in most milling surfaces, but not in broken surfaces. However, results also indicated that environmentally absorbed lipids formed a significant portion of the total lipid content. Thus, it is suggested that future analyses employ a biomarker approach, rather than criteria based on ratios of common fatty acids, to identify sources of organic residues in prehistoric milling tools.     

Archaeometrical study of Khmer stoneware from the Angkorian period: Results from the Cerangkor Project

In the area around Angkor, Cambodia, several ceramics kilns dating from the ninth to 15th centuries ce have been discovered since 1995. The technical, typological and compositional characterization of their production has been one of the main goals of the Cerangkor Project. Samples of green‐glazed ‘Kulen‐type' stoneware and non‐glazed stoneware produced in five kiln sites in the Angkor region were analysed chemically by wavelength‐dispersive X‐ray fluorescence spectrometry (WDS‐XRF) and also petrographically. The data indicate that some workshops used similar raw materials for the same types of ceramics, suggesting the exploitation of the same geological formations in the whole region. Several references groups were established for each type of stoneware offering an important database for future provenance studies of sherds from consumption sites.     

The Reliquary Bust of Saint Lambert from the Liège Cathedral,Belgium: Gemstones and Glass Beads Analysis by pXRF and Raman Spectroscopy

The reliquary bust of Saint Lambert, hosted in the Treasure of the Liège Cathedral, was produced in the early 15^th century. This exceptional goldsmithery piece is covered with gold-coated silver, and decorated by approximately 400 stones, analysed by Raman and pXRF techniques to determine their mineralogical and chemical composition. The results confirm the identification of one hundred pearls, twenty-six rock crystals, ten amethysts, two diamonds, and numerous glass beads with a green, blue, colourless, turquoise, orange or red colour. The glass beads show a soda-lime composition, confirming that they are contemporary of the bust and imported from Venice, as reported by historical sources. Orange beads show a lead composition and the red stone a triplet with quartz, indicating that they were added to the bust later. The cutting of gems and beads shows also a significant evolution. The metal contains approximately 60% of Au and 40% of Ag. The origin of gemstones was difficult to establish, due to the absence of characteristic trace elements, but the chemical elements used for the manufacture and colouring of the beads were determined. This study confirms the trade of stones between Liège and Venice during medieval times.     

Archaeometrical characterization of pigments and paintings on Pre-Hispanic pottery from the regions of Fiambalá and Chaschuil (Catamarca,Argentina)*

The results of an analysis of pigments used in slips and designs deployed in ceramic assemblages recovered from archaeological sites located in different environments, expressing the socio-historical process developed in the regions of Fiambalá and Chaschuil (Catamarca, Argentina) during the last 1500 years are presented. The sample, formed by fragments of different ceramic styles and natural pigments, was analysed via Raman spectroscopy and X-ray diffraction. Results indicate the continuity in use of certain pigments (mainly hematite for red hues and Mn oxides in combination with magnetite for black paints) within the different socio-political organizations that inhabited the region from the first to the 14th centuries ce , in spite of the diverse shades of colour, which suggests an intentional search linked with their cultural conventions. For the Inca Period, this scenery of continuities in minerals employed for reds and blacks is complemented by the use of new compounds (Ti oxide, apatite and gypsum) in order to generate the ‘cream’ tones applied as slips, all of which have not been identified for previous moments.     

Early Opacifiers In The Glaze Industry Of First Millennium bc Persia: Persepolis And Tepe Rabat

This study characterizes the opacifiers and colouring agents used in the glazed bricks of Persepolis (mid‐first millennium bc ) and the Mannean site of Tepe Rabat in north‐western Iran (eighth to seventh centuries bc ). Various analytical studies show that lead antimonate and brizziite (NaSbO₃) were used as the yellow and white opacifiers in the glazes of Persepolis and Tepe Rabat. Brizziite is shown to be incorporated in the white, green and turquoise glazes, and is also associated with lead antimonate and CaSb₂O₆ in some yellow and white opacifiers. The simultaneous formation of these opacifiers in one glaze might have been accidental. A possible connection between the Achaemenid glaze industry and the Mannean glaze production at Tepe Rabat is discussed.     

A Multi‐Analytical Approach to the Study of the Mural Paintings in the Presbytery of Santa Maria Antiqua Al Foro Romano in Rome

This paper presents the results of analyses carried out on three decorative phases of the presbytery of the church of Santa Maria Antiqua al Foro Romano in Rome: the fourth‐century ad mosaics setting bed; the Adoration of the Cross, dated to the papacy of John VII (ad 705–7); and the paintings in the apse of the Pope Paul I (ad 757–68) phase. The research allowed the characterization of the painting techniques, pigments, organic compounds and degradation products by means of a video microscope, optical microscopy, and μ‐Raman and FT–IR spectroscopy, contributing to a better understanding of the changes in the techniques and materials used throughout the centuries in one of the most relevant medieval Christian monuments in Western Europe.     

湖北随州叶家山西周墓地出土青铜器锈层结构的综合分析

为研究湖北随州叶家山西周墓地出土6件典型青铜器残片的锈蚀特征,利用超景深三维视频显微分析、X射线荧光光谱(XRF)、离子色谱、拉曼光谱(Raman)及扫描电镜能谱面扫描分析(SEM-EDS Mapping)等方法对其进行了综合分析。研究结果表明:叶家山墓地墓葬多为中性/弱酸性、贫氯埋藏环境,有利于青铜器的保存。其锈层结构丰富,符合基于水与青铜器模拟腐蚀过程所推导的锈层结构类型。唯M46为弱碱性、富氯的埋藏环境,该墓出土残片锈蚀中存在有害锈,属于典型"粗糙疏松"锈层类型,亟须对该墓出土其他铜器进行相关保护处理。本研究系利用拉曼及扫描电镜能谱面扫描分析等方法对古代青铜器锈层结构进行原位、综合分析的工作。实践指出,利用拉曼及扫描电镜能谱面扫描分析等方法,可快捷、高效、有针对性地分析古代青铜器的锈层结构。     

Colouring Agents in the Pottery Glazes of Western Anatolia: New Evidence for the Use of Naples Yellow Pigment Variations During The Late Byzantine Period

A group of the late 12th–13th century Byzantine pottery glazes, mostly related to Zeuxippus Ware Type pottery from the Ku?adas? Kad?kalesi/Anaia site in western Anatolia, was characterized non‐destructively using Raman spectrometry. SEM–EDX was also used complementarily for the glaze characterization. The nature and composition of the glazes, firing conditions, aspects of colour formation and pigments used were discussed. The glazes were found to be lead‐rich silicates, fired close to 700°C on the basis of the Si–O stretching peak maxima of the Raman spectra recorded at ～920–980 cm^–1, as also confirmed by SEM–EDX analysis. The polymerization index values calculated are between approximately 0.05 and 0.1. The use of biscuit‐fired bodies prior to glaze application was suggested based on the results of SEM–EDX analysis. In particular, the detection of Naples yellow pigment variations on a locally produced pottery sample is quite significant, since the use of this type of pigment has hardly ever been reported between the Roman period and the Renaissance.