40004710, Marlborough, 10, Portrait (profile left): Mithridates VI of Pontus (Vollenweider). Bust of a figure with long curly hair and an ivy wreath., Geneva, Musée d'art et d'histoire, Boardman, J., Scarisbrick, D., Wagner C., Zwierlein-Diehl, E: The Marlborough Gems (2009), Story-Maskelyne, M.H.: The Marlborough Gems (1870), 23478, Cameo, Sardonyx