Sources of Magnesium Efflorescence on Ceramics ABSTRACT AUTHORS Magnesium formate dihydrate was detected by Raman microscopy Gerhard Eggert* Emeritus Professor of Objects' as efflorescence on terracotta figures with replacements made of Conservation Sorel’s magnesia cement consisting of basic magnesium chlorides Institute of Conservation Sciences State Academy of Art and Design as binder phases. On this alkaline, not water-proof material, Stuttgart
[email protected] formaldehyde from indoor air pollution can react directly to formate via the Cannizzaro reaction causing the efflorescence. Judith Berning MA Student Objects' Conservation Programme Hairy, wooly aggregates of curved needles, resembling State Academy of Art and Design thecotrichite, were found on Attic black-figured vases and Stuttgart
[email protected] identified as magnesium sulfate hexahydrate, mineral name: stuttgart.de hexahydrite. As no gypsum was present, migrating salts from Andrea Fischer the architecture in a necropolis are considered as a magnesium Senior Lecturer Objects' Conservation Programme source. The appearance is not due to a certain material, but due to State Academy of Art and Design Stuttgart crystallisation on a porous substrate with a dry surface.
[email protected] Samples of efflorescence should generally be kept in order to Jörg Stelzner Researcher/Objects' Conservator enable subsequent instrumental analysis, which may add to the Institute of Conservation Sciences objects’ ‘biographies’. State Academy of Art and Design Stuttgart
[email protected] KEYWORDS Sebastian Bette Researcher/Chemist Ceramics · Efflorescence · Hexahydrite · Max Planck Institute for Solid State Research Magnesium formate · Magnesium oxychloride ·
[email protected] Magnesium sulphate · Sorel · Whisker *Corresponding Author INTRODUCTION Conservators of archaeological ceramics Magnesium, if present in clay, is tightly bound in sometimes have to deal with salt deposits and the ceramic matrix; mobilisation and dissolution efflorescence.