Lot Essay
For comparable obsidian and rock crystal models of seals, see C. de Guitaut, Fabergé in the Royal Collection, London, pp. 88-89, no. 86 (RCIN 40811), illustrated, and G. von Habsburg-Lothringen and A. von Solodkoff, Fabergé: Court Jeweller to the Tsars, London, 1979, p. 78, pl. 92.