This rare collar is similar to four in the Palace Museum, Beijing. Three of these collars in the Qing Court collection are illustrated in The Complete Collection of Treasures of the Palace Museum - 51 - Costumes and Accessories of the Qing Court, Hong Kong, 2005, p. 231, no. 147, which appears to be in natural ivory; pp. 233-4, no. 148, which has been stained green; and pp. 256-7, no. 149, where the ivory is also unstained. A red-stained ivory example is illustrated by E.S. Rawski and J. Rawson, eds., in China: The Three Emperors, 1662-1795, Royal Academy of Arts, London, 2005, p. 143, no. 48.