scagliola is a composite substance made from selenite, glue and natural pigments, imitating marble and other hard stones. the material may be veined with colours and stuck on to a core, or patterns may be carved into a prepared scagliola matrix. the pattern is then then filled with the coloured, plaster-like composite. then it is polished with flax oil for brightness, and wax for protection. the whole thing gives a richness of colour not easy to get in natural marbles.