Uranium glass in museum collections

Journal of Cultural Heritage, nº 9 (2008), p. 64-68The presence of uraniumglass objects in museum and private collections has raised radiation protection concerns resulting from possible exposure to ionizing radiation emitted by this type of object. Fourteen glass objects with different uranium contents were studied. Dose rates (b þ g radiation)were measured with a beta/gamma probe at several distances fromthe glass objects. In general, the determined dose rates did not raise any concern as long as some precautions were taken. Radon (222Rn), usually the most important contributor for the overall natural dose exposure resulting from radium (226Ra) decay in the uraniumnatural series, was also evaluated and it was found to be within the background values. Non-invasive analyses of the uranium content were made using micro-EDXRF analysis, measuring the radiation emitted by the objects and fluorescence spectroscopy

Mineralogical Characterization of Hispano-Moresque Glazes: A μ-Raman and Scanning Electron Microscopy with X-Ray Energy Dispersive Spectrometry (SEM-EDS) Study

This work explores the combination of μ-Raman spectroscopy and scanning electron microscopy with X-ray energy dispersive spectrometry (SEM-EDS) for the study of the glazes in 15th–16th century Hispano-Moresque architectural tiles. These are high lead glazes that can be tin-opacified or transparent, and present five colors: tin-white, cobalt-blue, copper-green, iron-amber, and manganese-brown. They are generally homogenous and mineral inclusions are mostly concentrated in the glaze-ceramic interface. Through SEM-EDS, these inclusions were observed and chemically analyzed, whereas μ-Raman allowed their identification on a molecular level. K-feldspars, wollastonite and diopside were the most common compounds, as well as cassiterite agglomerates that render the glaze opaque. Malayaite was identified in green glazes,and andradite and magnesioferrite in amber glazes. Co–Ni–ferrites were identified in blue glazes, as well as Ni–Fe–olivines. Manganese-brown is the color where most compounds were identified: bustamite, jacobsite, hausmannite, braunite, and kentrolite. Through the μ-Raman analysis of different areas in large inclusions previously observed by SEM, it was possible to identify intermediate phases that illustrate the reaction process that occurs between the color-conferring compounds and the surrounding lead glaze. Furthermore, the obtained results allowed inference of the raw materials and firing temperatures used on the manufacture of these tiles