40004613, Marlborough, 16, Bust of Athena (?) with a mask and vine on her helmet., Unknown, Boardman, J., Scarisbrick, D., Wagner C., Zwierlein-Diehl, E: The Marlborough Gems (2009), Story-Maskelyne, M.H.: The Marlborough Gems (1870), no. 16, Cameo, Sardonyx