Unusual hallmarking on a ring

Normally ring hallmarks are on the inside of a ring, requiring a special ‘swan-necked’ punch, but I was asked to produce one with the hallmarks on the outside.

SIlver ring with external hallmarks
SIlver ring with external hallmarks

Here the London Assay Office have applied ‘display’ marks that are deep and durable.  I’ve also been able to employ one of my slightly larger straight punches.