A hallmark is an official mark on a piece of jewellery or item made from a precious metal. Hallmarks exist to protect consumers as they prove the type of metal and its quality, and also provide evidence of who made the piece and when.
A full traditional hallmark is made up of five marks and looks like this:
Sponsors’ (or Maker’s) Mark
The JMG inside an oval is unique to me and means that anyone can look up the hallmark on a piece I have made and find out that it was made in my workshop. Each maker or manufacturer has a unique Sponsors’ mark, which normally takes the form of initials surrounded by a shield design. The shield shape is important as there may be multiple makers who have the same initials, therefore the shield helps identify the exact maker of the piece. Each shape and initial combination is unique so can only be linked to one maker or manufacturer.
Traditional fineness mark
The traditional fineness symbol is an optional part of the hallmark but is applied as standard by my local Assay office in London. The photograph of my hallmark above shows the fineness mark for Silver.
From left to right: Sterling Silver, Britannia Silver, Gold, Palladium, Platinum
Millesimal fineness mark
This number tells you how fine the metal is, as well as indicating what the metal is through the shape of the shield. This is a format introduced in 1999 and tells you the precious metal content of the item, expressed in parts per thousand.
The peaked rectangle represents Platinum and the three connected circles represent Palladium – this difference in shape is very important as the fineness is the same in these two metals (950)
Gold is depicted in a rectangular octagon – 18ct gold = 750 and 9ct gold = 375. These are the standard finenesses used in the UK but you may also see 585 which is 14ct and 916 which is 22ct gold.
Silver is represented with an oval. 925 is the most common fineness of Silver seen in the UK and this is known as Sterling Silver. If you see 958 within an oval, then this is Britannia Silver.
From left to right: Platinum, Palladium, 18ct gold, Sterling Silver
If a piece is made of mixed metal, it will be marked to the lowest standard of alloy content, so this guarantees that the quality of the article is no less than the fineness indicated.
Assay Office mark
The Assay Office mark tells you which Assay Office tested and hallmarked the item. This gives you an idea of the location of the maker or manufacturer. I live in the South East of England so my local Assay Office is London, therefore my work always features a Leopard’s head in the hallmark. Where a maker or manufacturer is located further north, they may use the Sheffield or Birmingham offices. The fourth office is located in Edinburgh.
Left to right: London, Birmingham, Sheffield, Edinburgh
Date letter mark
The date mark is not compulsory but I feel it is an interesting element to include as jewellery is built to last a lifetime and it adds to the history of the piece. In wedding rings, I feel it is a nice touch to have the date stamp inside the ring, especially if it matches the year of the marriage.
The date letter changes annually on January 1st. The font of the letter and the shield shape it is surrounded by change so that each can only indicate one specific year.
These marks are applied at the end of the hallmark and are struck to commemorate a special event, for example, the Diamond Jubilee.
How the hallmark is applied
Hallmarks are either stuck by hand using a punch, or by a laser. Both methods create an impression in the metal. I usually use the laser service as the size of the mark can be altered to suit the individual pieces.
When you next purchase a piece of jewellery, check out the hallmark because it will tell you more about the provenance and history of the piece as well as the type of metal it is made from. Most jewellers will have a jeweller’s loop which will help you to see the marks more clearly.