M. Járó - L. Költő szerk.: Archaeometrical research in Hungary (Budapest, 1988)

Analysis - ZIMMER Károly: Spectrochemical investigation and classification of Hungarian glass finds

For the colour of the object in the green class, copper and iron are responsible

, the blueish-green shade is due to a higher Cu and Mn and a lower Fe content. In the blue class, light and dark shades can be distinguished; a major part is played in this by the Cu and Mn content. A unique situation occurs with the brown and black classes: only one sample each was available for these classes. In the former case the significantly high Fe content and relatively high Mn content (and a relatively high Ti, Cr and V content) are typical, in the latter the relatively high Fe content and the strikingly high Ti content are typical, in agreement with literature data. All results obtained are in good agreement with the data found in the literature. In the 3rd—4th century of our era the glass colouring technique used nowadays was not yet known, and colouring effects were achieved by using the compounds of certain elements (like Cu, Pb, Fe, Mn, Sb and, in part, Sn and Ti) and by combining the different amounts of these compounds. A typical example is copper which, depending on the given oxidation state and additive, acts as a red, blue, green or even black colourant. The concentration of some further elements, like Pb and Sn, and in certain cases Mn and Fe (for these elements the colouring effect could not be shown in all cases) can be explained by the application of metallurgical slugs for glass colouring [13]. Investigation of mediaeval glasses of Buda Castle Systematic investigations have been carried out on fragments of the mediaeval glass relics of Buda Castle. By means of the determination of main, major and minor elements, the pigment materials can be established, whereas knowledge of the accompanying and trace elements gives the possibility of drawing conclusions about the origin of the glasses. These investigations have been performed by colorimetry, X-ray fluorescence and d. c. arc AES methods [14]. The ICP-source was successfully used for the investigation of silicate rocks [15] and traditional glasses [16, 17]. Very good results were also obtained by using the glow discharge source for the determination of trace elements in silicates [18]. The investigation of archaeological glasses in comparison with silicates and traditional glasses poses new problems, however, owing to he different chemical composition, structure and moisture contents, the small samples available, and the special care required in sample pretreatment and preparation of standards. On the basis of the favourable literature experiences mentioned, we aimed at the development of analytical methods using ICP and glow discharge sources for the determination of the microcomponents of the mediaeval glasses. Analysis by ICP. In the current practice of ICP spectrometry a stable solution is a prerequisite. For traditional glasses and vitreous materials two different methods of solution preparation have usually been used in decomposition methods: (a) digestion and (b) alkali fusion [19, 20]. For both dissolution methods many alternative procedures are employed. Calibration samples of a known composition and of natural origin were not available in the spectral analysis of non-conducting materials like glasses, hence we had to use synthetically produced cahbration samples. The composition of the model base was in agreement with the contents of the glasses to be analysed. The main components such as Si, Ca, Mg, Na and K of some glass samples were detennined by means of thermometric analysis and consequently the following matrix composition was employed: Si0

2 66%, CaO 11%, Na

2 0 7%, K

2 O 11%, MgO 5%. The glass samples were digested with a mixture of sulphuric, nitric and hydrofluoric acids. The investigations were carried out with an ARL 35000 Quantoscan ICP spectro-