A hallmark is a UK Government seal which is stamped onto precious metals to certify the metal purity of the item. In other words, if an object is stamped with a ‘silver’ hallmark, then you can be assured that the item is indeed real silver, not something else that simply looks like silver.
A hallmark must consist of at least three compulsory marks; a Sponsor’s/makers mark (mine is MR inside a double circle), a Metal Fineness mark (925 for sterling silver), and an Assay Office town mark (a castle which is the Assay Office mark for Edinburgh). My hallmark also includes a traditional Metal Fineness mark of the Lion Rampant (for Sterling silver).
All sterling silver items over the weight of 7.78g must legally be hallmarked in the UK.
For more information on hallmarking, please click here.