Chemical Composition of 16th- to 18th-Century Glass Beads Excavated in Paris

Dating from the 16th to 18th centuries, 63 glass artifacts (mostly beads) recovered from two sites in Paris, France, were investigated using chemical analysis in an attempt to determine their place of origin. The late-16th-century material from the Jardins du Carrousel consisted of small, monochrome drawn beads with a soda-lime composition. Attributed to the 17th and 18th centuries, the beads recovered at the adjacent site of the Cours Napoléon were more diverse in shape, color, and composition. Although provenance attribution was difficult due to a lack of comparative data, it was possible to identify an increasing variety of glass recipes after the 16th century that revealed a growing interest in glass beads in Europe. In the 17th century and afterwards, greater numbers of glass- and glass-bead production centers were active, quite certainly due to a growing demand for export goods but also due to a more extensive use of beads in France

Mycenaean beads from Kazanaki, Volos: a further node in the LBA glass network

Finished glass objects are found in large quantities scattered throughout Egypt, Mesopotamia, the Levant, and the Aegean during the late second millennium BC. We propose that glass was primary produced in a few centres, then transferred and exchanged to the more widely available secondary glass making workshops throughout the Eastern Mediterranean. Glass was used and consumed in the Mycenaean world, however there have not been many studies discussing its provenance. The present paper examines glass beads found in a tholos tomb at Kasanaki, which is located in the inlet of the Pagasetic Gulf where actually functioned the big palatial center of Iolkos, with whom the tomb is certainly connected. We attempt to investigate the production, exchange and consumption of glass in Late Bronze Age (LBA) Mycenaean Greece. The samples were analysed using Electron Probe Microanalysis and Scanning Electron Microscopy to determine their chemical composition and identify their raw materials. The present study characterises the glass from Eastern Thessaly -in fact from a site located in the biggest port of Central Greece from where all the commercial exchanges of Thessaly with the Aegean World were taking place - and positions it within a broader compositional group. Performing multivariate analysis of the major elements and comparing our samples with LBA glass from the literature, it is examined whether the glass was made locally or internationally exchanged. The paper adds to our current knowledge of glass manufacturing in the LBA mainland Greece

New Data on Source Characterization and Exploitation of Obsidian from the Chikiani Area (Georgia)

This paper presents the results obtained from two brief surveys carried out in 2012 and 2014 along the slopes of Mt. Chikiani in south Georgia. The scope of the surveys was to collect obsidian samples for characterization, to improve our knowledge of the raw material resources exploited in prehistoric times. The analysis of 69 samples retrieved from 20 different points have confirmed that Chikiani obsidian is to be subdivided into 3 main groups, characterised by variable percentages of barium and zirconium. The new results have important implications in the prehistory of the Caucasus and its related regions. They improve our knowledge on the exploitation of the obsidian resources, and their circulation in the territory

Refining silver with glass and soap: experimentation with an atypical recipe from the Probierbüchlien of 1524

Pour les périodes anciennes, l’affinage de l’argent se pratique classiquement par coupellation. Il existe cependant d’autres procédés permettant d’obtenir un argent pur. En se basant sur une recette du début du XVIe siècle, nous montrons grâce à l’expérimentation archéologique la pertinence d’un traitement d’un alliage argentifère par ajout de verre et de savon. L’approche archéométrique sur les argents produits comme sur les verres permettent de qualifier les différentes productions expérimentales. Nous montrons également la filiation de ce procédé depuis le Xe siècle jusqu’au XXe siècle.For the ancient periods, the refining of silver is classically practiced by cupellation. However, there are other processes that can be used to obtain fine silver. Based on a recipe from the beginning of the 16th century, we show through archaeological experimentation the relevance of treating a silver alloy by adding glass and soap. The archaeometric approach on the refining silvers as well as on the glasses allows to qualify the different experimental productions. We also show the filiation of this process from the 10th century to the 20th century

The role of sulphur in the early production of copper red stained glass

Little is known about the production of ruby red copper stained glasses from the Medieval and Renaissance periods apart from the fact that the colour is due to the presence of small metallic copper nanoparticles and that tin, the most common reducing agent used in copper red glass production since the 19th century, is not present. In fact, very few workshops in Europe were able to make red glass in historical times, and they kept it secret, so very little is known about how it was obtained. These workshops exported the red glass throughout Europe. Recently, the presence of copper sulphide particles and the data obtained in the replication red glass following historical recipes suggested that sulphur might be the key ingredient in this process. Here, a collection of historical red glasses from these periods has been analysed using a combination of microanalytical techniques; Electron Microprobe (EM) and Field Emission and Scanning Electron Microscopy (FESEM) to verify the chemical composition and nanostructure of the glasses, Synchrotron radiation micro-X-Ray Diffraction (micro-XRD) to establish the nature of the nanocrystalline precipitates, and S, Cu and Fe K-edge micro-X-Ray Absorption Spectroscopy (micro-XAS) to determine the speciation. The data obtained show that the oxidation of S2- into S6+ in the glass is responsible for the precipitation of copper nanoparticles. The development of a sulphide-silicate partition and the presence of Fe3+ in the melt give rise to the precipitation of the high-pressure tetragonal polymorph of chalcocite (Cu2S). Differences between the Medieval and Renaissance red glass are determined.Peer ReviewedPostprint (published version

Le mobilier en verre du site de la Grotta Piatta (Aregno, Haute-Corse) : composition chimique et chronotypologie

La Grotta Piatta est un site funéraire protohistorique découvert sur la côte Nord occidentale de la Balagne. Un nombre important de perles en verre y a été révélé. Sur les trois cent soixante-neuf pièces recueillies, une vingtaine a fait l’objet d’analyses pour déterminer leur composition ainsi que leur provenance. L’analyse a mis en évidence l’origine proche orientale de la pâte de verre utilisée comme matière première ; trois grands groupes ont été distingués, par rapport aux fondants et aux sables utilisés dans leur composition. Cependant, certains éléments ont montré des particularités. Chronologiquement, ce mobilier peut être rattaché à un contexte postérieur au iie siècle av. J.-C. et postérieur au ier siècle de notre ère, pour trois éléments se distinguant.Grotta Piatta is a funerary protohistoric site discovered in the Western Northern coast of Balagne, where a significant number of glass beads was discovered. Out of the three hundred sixty-nine parts collected, about a score have been analysed to determine their source and composition. The analysis highlighted the Near-Eastern origin of the molten glass used as raw material; three important groups were distinguished in relation to the fluxes and sands used in their composition. However, some elements showed specific. Chronologically, this furniture can be linked to a context posterior to the second century before Christ, except for three different elements posterior to the first century of our era

Les objets de parure en black shales à l’Âge du Fer en Europe celtique : recherche de provenance par l’analyse élémentaire (LA-ICP/MS)

Certaines roches sédimentaires, notamment les black shales ont servi à fabriquer des objets de parure pendant l’époque celtique. Ces matériaux sont peu étudiés et les études de caractérisation spécifique peu nombreuses. La présence récurrente de ces objets observés à une large échelle géographique pose plusieurs questions sur la provenance de ces matériaux. Or, la caractérisation de ces derniers constitue la base de toute étude de provenance. La filiation entre les matériaux archéologiques et les sources géologiques demeure essentielle dans la restitution des échanges. L’apport de l’analyse élémentaire par spectrométrie de masse couplée à un plasma inductif avec prélèvement par ablation laser (LA-ICP/MS) permet d’établir des distinctions entre les divers matériaux. Cette approche permet de dresser un premier bilan. Certains éléments chimiques tels que le tungstène, le molybdène, le lithium, le césium et le rubidium sont discriminants au sein des différents matériaux. Des gisements de différentes régions présentent des caractéristiques chimiques distinctes. Des rapprochements sont faits entre des artefacts archéologiques et des gisements géologiques situés à proximité du site. Cependant, l’attribution des objets archéologiques à des gisements géologiques passe par un meilleur inventaire des sources potentielles.Some sedimentary rocks, especially black shales, were used to make objects such as pendant jewelry during the Celtic period. These materials are not often studied and there are not many specific characteristic studies. The recurrent presence of these artefacts which are studied on a large geographic scale bring up many questions about the origin of these materials. Usually, the origin studies are based on the characterization of materials. The filiation between archeological artefacts and their geological sources is essential in the restoring of the exchanges. The results of the elementary analysis using laser ablation inductively coupled plasma mass spectroscopy allows to establish distinctions between these different materials. This approach allows to set up a first conclusion. Some chemical elements such as tungsten, molybdenum, lithium, caesium, and rubidium are discriminants within the different materials. Some outcrops from various regions present different chemical characteristics. Links can be established between archaeological artefacts and geologic deposits situated near the site. However, the attribution of the archaeological materials to geologic outcrops requires a better inventory of the potential sources