Chemical Composition of Glass and Traditions of Enamellers in Eastern Europe in the Late Roman Period (a Case Study of the Bryansk Hoard) (original) (raw)
Related papers
Chemical Characterization of Roman Glass Vessels, Enamels and Tesserae
MRS Proceedings, 1990
Chemical characterization of Roman glass vessels, enamels and tesserae has revealed compositional relationships between enamels and tesserae including the use of high magnesia red and orange glass, normally considered to have gone out of use hundreds of years earlier. The conservative use of glass recipes over a 300 year period is reflected in the compositions; the results of mass-production versus more restricted production are discussed.
Journal of the American Ceramic Society, 2013
We studied ancient enamels on gilded copper from a collection of archeological horse harness pendants of the Museo Instituto Valencia de Don Juan (Madrid, Spain) to test the benefits of a new, nondestructive analytical methodology based on chemometric analysis (i.e., Principal Component Analysis, PCA) on micro-ATR-FTIR spectral data and chemical quantification using SEM-EDS. The novelty of this approach was threefold: (i) PCA allowed the discrimination of the different harness pendants of known origin and attributed to the 14th and 15th centuries according to the chemical complex composition, nanostructure, glass weathering, and/or coloring mechanisms of each colored enamel, separately (i.e., red, purple, blue, and white), (ii) it is a cheap, easily available and nondestructive methodology that enables us to (iii) draw archeological conclusions about the quality of the manufacturing process, reassess the chronology of these objects and attempt to attribute them to different workshops according to the different traditional recipes identified. In particular, the enamels were made of alkali and/or alkaline earth lead-glass with a wide range of chemical compounds in the form of pigments or opacifiers. Two types of coloring mechanisms were identified, colloidal particles such as copper-ruby for red enamels, and ionic mechanisms such as Fe(II) and Co(II) to achieve a blue pigments; Mn(III) in the purple pigment; and two kind of white enamels were identified, i.e., tin oxide as an opacifier and uranium oxide. In addition, we established the reason for the poor state of conservation of some of the enamels by means of the identification of depolymerization and ion exchanges, well-known harmful effects of glass weathering, and finally a chronology was assigned for some of these pieces according to the enamel composition.
2020
This paper is devoted to the interdisciplinary study of an enameled glass fragment found in the excavation of the Bolgar fortifi ed settlement (Russia). The artifact comes from excavation site CLXXII of the so-called aristocratic district of the city. A comparison to a collection of Islamic drinking glasses from the Nasser Khalili collection shows the identity of the enamel pattern decor. The artifact was investigated by a series of analytical methods: scanning optical and electron microscopy (OSEM) and optical emission spectral analysis (OES). The results of the OES studies revealed that the basis is soda-lime glass. OSEM determined that different enamel colors were obtained from lapis lazuli, nepheline, diopside, bone ash, hematite, and lead-tin additive. Comparison of element's concentrations with data of the Brill catalog of archaeological glass made it possible to identify the Bulgarian fragment as Egyptian glass produced in the late 13 th-early 14 th centuries.
X-Ray Spectrometry, 2010
In this study, the results of analysing of a series of 16th-19th century painted enamel objects of the Limoges School currently in collections in three Dutch and Flemish museums by means of portable and micro x-ray fluorescence analysis (PXRF and µ-XRF) and electron probe micro analysis (EPMA) are presented. The aim of the investigation was the authentication of specific pieces. Therefore, the glass compositions as well as the (glass) colouring agents used by the Limoges' artists were studied as a function of the age of the objects. Due to the evolution of these properties, it is possible to approximately date these objects based on their chemical composition. The complete 'émail peint' collection of the Museum Boijmans-Van Beuningen (Rotterdam, The Netherlands), consisting of 20 'émail peint' plaques, was analysed with µ-XRF.
CHARACTERIZATION OF THE CHEMICAL COMPOSITION OF MEDIEVAL GLASS FINDS FROM SOUTH BULGARIA
2015
PIXE and PIGE were used for determination of 23 elements in 50 glass samples excavated in Zlatna Livada-South Bulgaria (dated 11 th-12 th century AD). Elemental concentrations show that the analyzed fragments belong to soda-lime-silica glasses. Cluster analysis and bivariate plots indicate the use of natron, plant ash and mixed alkalis as well as production according Near East and Roman-province recipes. The metal oxides responsible for coloration were also investigated. The blue and blue-green colors are due either to CoO or to high concentration of FeO (blue: 3.3-6.3%, blue-green: 1.23-2.83%), melted in reducing atmosphere. The melting under oxidizing environment determined the higher oxidation state of iron oxide and the green color of some of the glasses (0.7-3.4% Fe2O3). Different shades of brown color are due to the high concentration of Fe2O3 (2.4-4.9%) and Mn2O3 (0.3-0.7%) melted in oxidizing atmosphere. Discoloration of the glasses is achieved by the presence of high amount of MnO (0.6-2%). A comparison to other medieval Bulgarian glasses was performed.
ON THE ORIGIN OF ENAMEL‐PAINTED GLASS OF THE 12 ‐ 14th CENTURIES IN BOHEMIA
ANNALES du 18e CONGRÈS de l’ASSOCIATION INTERNATIONALE pour l’HISTOIRE du VERRE Thessaloniki 2009 Editors Despina Ignatiadou, Anastassios Antonaras, 2012
The haematinon bowl from Pydna. Height 5.5 cm. © 27 th Ephorate of Prehistoric and Classical Antiquities, Greece. The bowl (skyphos) is discussed in the paper by Despina Ignatiadou ' A haematinon bowl from Pydna' , p. 69.
Polychrome enamels, ceramics, glasses and their degradation
HAL (Le Centre pour la Communication Scientifique Directe), 2021
Due to the good chemical stability of chemical bonds forming silicates, glass and pottery are generally well preserved and can be used as dating milestones. After a brief recall of the preparation of (glazed/enamelled) pottery and glass (utensils, stained glass windows) from the technical and historical points of view, the main chemical and physical characteristics of the glassy materials (composition, mechanical and thermal characteristics, porosity, etc.) are presented and discussed in relation to corrosion resistance. The corresponding analytical techniques are addressed. Emphasis is given on the different mechanisms of degradation (surface and bulk corrosion, crazing/peeling, proton/water insertion, lixiviation, oxidation) as well as conservation and restoration practices. Dating/authentication of ancient artefacts by the measurement of Raman signal at the surface of glassy silicates is further presented. 4.1 Definitions Pottery, glass and enamelled artefacts are made of silicon-and aluminium-rich inorganic matter, namely the silicates which are the main constituents of the earth. These artefacts are made by thermal treatment of powdered rocks/minerals, such as sands, clays, feldspars and calcareous stones. 1-8 The silicate structure consists of the association of SiO 4 tetrahedron with AlO 4 or FeO 4 tetrahedron, AlO 6 or FeO 6 octahedron and similar chemical units in between which isolated ions may be located. 5,6 These structures can be crystalline or glassy. While glass is obtained by full/complete melting of the raw materials shaped at high temperature, using the controlled viscosity of molten glass, pottery is shaped before heating in the 'green' state taking advantage of the plasticity of humid clay mixture in which grains will be cemented and welded by firing. Enamels are any kind of glassy coatings (Fig.1) deposited and fired on a substrate (ceramic, glass or metal), already fired or in green state. A coating on pottery is called glaze. All processes involve powdering the raw materials in order to promote their reaction and homogenisation on heating. Due to the huge stability of Si-O and Al-O bonds, heating at high temperature is required to break and constitute the bonds again (sintering) and/or form new phases by reaction (dissolutionprecipitation): temperatures ranging between 500°C and 1400°C are usually needed for silicates. 7 Higher temperatures may be required for advanced non-silicate technical ceramics and glasses. Achievement of a non-porous ceramic body usually requires temperatures higher than 1100-1200°C and total melting may typically occur between 600°C (lead-rich silicate) and 1500°C (fluxpoor silicate), depending on the exact composition. 7-9 Consequently, ceramic, glass and enamel wares are very stable and well preserved for millennia and thus used to date archaeological layers. For instance, in African tropical countries where the preservation of carbon-based artefacts is difficult, dating of an archaeological layer is based on a specific pattern of pottery decor as well as the use of trade beads coming from the main places of production (chronologically Mesopotamia, Egypt and the Mediterranean world, India-South/East Asia, China and Europe) through particular routes (Indian Ocean and Monsoon wind shipping , trans-African terrestrial network). 10-11 Similarly, the habit and typology of tools made of natural silicates (obsidian, flint, cherts, cornelian, etc.) allow the dating of prehistorical archaeological contexts. 12,13