Ruby colouration, to judge from the bowls and fragments which have survived to the present day, was highly sought after by the ninth century potters but rarely well-achieved. One remarkable fragment now in the Khalili Collection has a ground of an intense scarlet (Grube, Ernst J.: Cobalt and Lustre, London, 1994, no.19, p.27). Other examples where the rich red is tried but with less brilliancy are in the Keir Collection (Grube, Ernst J.: Islamic Pottery of the Eighth to the Fifteenth Century in the Keir Coollection, London, 1976, nos. 10 and 11, pp.47 and 49) and in the al-Sabah Collection (Jenkins, Marilyn (ed.): Islamic Art in the Kuwait National Museum, London, 1983, p.22). See also lot 276 in this sale.