40004624, Marlborough, 181, Frontal Medusa head with wings and snakes in hair and at neck., Unknown, Boardman, J., Scarisbrick, D., Wagner C., Zwierlein-Diehl, E: The Marlborough Gems (2009), Story-Maskelyne, M.H.: The Marlborough Gems (1870), M555-1910, Sapphire