Scagliola is an inlay work of various coloured, smoothed and polished stucco pastes. Recipes from various written sources mention "alabaster-gypsum" as the basic material. The actual Italian meaning of scagliola is gypsum calcined between 130° and 170°C. The name "scagliola" originates probably from a variety of gypsum (Italian: gesso) used - selenite - a kind of gypsum made of transparent and translucent scales ("scaglie"). The scagliola technique was invented by stuccoists working in Bavaria in the 16th century. Italian artists working in Germany introduced Italianate designs. The technique appeared in Italy during the baroque period, with the cult of illusionism. It was used to imitate marble and was popular in the 17th and 18th centuries for architectural features. One of the most famous production centres of scagliola with marble imitation was Carpi in Italy. In the seventeenth century, "scagliola" was made using selenite or sericolite occurring in the Appennino Emiliano in Italy. The selenite was put in an oven at 300°C until it was broken and could be ground with mortar and pestle into powder that was then sieved. Adding water and animal glue (rabbitskin glue or parchment glue) retarded the set of the plaster and produced a thick paste that could be coloured. Additives included sand or marble dust, and lime. The mix was coloured with dry pigments and filled with coloured marble or alabaster chips. Veining was mimicked by dusting the surface with dry pigments. The surface was smoothed with a metal scraper. Once the plaster had set, the long process of polishing the surface with pumice stones and filling any voids with a plaster slurry was carried out. Finally the surface was rubbed with oil to produce a high sheen. Figurative and ornamental decorations could be made with this material, imitating at least to some extent the pietra dura technique in which stones are cut to form inlays, mostly on flat surfaces like e.g. altar tables. It was also used for ornamental panels and columns (Rowland and Riley 1981). For the decoration of larger architectural areas, the technique of scagliola was used to imitate natural stone rather than to recreate decorative drawings - this is, according to most sources, how stucco marble started to develop. Scagliola is softer than true marble and scratches easily. Inlaid scagliola, which resembles pietre dure, uses the same materials, applied over a rigid support such as slate. A solid background colour is laid down and the shapes to be inlaid are gouged out. Coloured is then pressed into the voids to build up the desired image and the surface is polished and oiled. Ashurst (1983); Wittenburg (1999); Trench (2000); English Heritage (2000); Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]