It is fashioned from various triangular amethysts set within pierced and foliate engraved millegrain mounts.
Although the vendor had little idea of its maker or history the survival of the original fitted case bearing both Dunlop's name and the embossed inscription Bishop of London simplified the task of research for Holloways of Banbury who offered it for sale on September 25.
Estimated at £800-1200, it sold to a private collector at £6000.