Hallmarks are legal markings stamped into precious metals by the British Assay Office. They denote the purity of the precious metal, as well as the origin of the item. Hallmarks are essential for proving the inherent value of your jewellery. You should never purchase a piece of fine jewellery without a hallmark, unless in rare cases that the piece is under the weight requirements for Assay.
Up until 1998, hallmarks were made up of four “compulsory marks”. The date mark has since become optional but the other three symbols remain compulsory. The compulsory symbols represent:
There are three compulsory marks that make up a modern hallmark. The first represents the alloy the item is made from. There are different shaped marks for gold, silver, platinum, and palladium. Each unique shape also contains a number which shows the purity of the alloy.
The next mark which makes up the hallmark is the Assay Office mark. There are four Assay Offices in the United Kingdom, located in London, Edinburgh, Sheffield, and Birmingham.
The final compulsory mark is the makers mark. This might be a mark unique to the jeweller you have purchased the item from, but it could also be the mark of the casting workshop who initially cast the piece.
There are a few ways in which a hallmark can be applied. The first is a hydraulic press which stamps the marks into the metal. For finer items, there is also the more traditional hand applied press. In recent times the Assay Office has also began to use a laser to apply hallmarks. This is particularly for hollow items, or items which are already finished.
Before an item can be hallmarked, the Assay Office will test it to ensure that the precious metal alloy meets the legal requirements of composition. No variation is allowed, so if, for example, an item of 9ct gold which should be 375 parts per thousand fine gold, tests at 374 it will not be hallmarked.
De to this strict rule, you can be confident that any item hallmarked by the British Assay Office is assured to be of the finest quality. This is also why we only sell precious metal items that are hallmarked in Britain.
The traditional method to Assay test items involves having a tiny amount of metal scraped away. This is then subjected to high temperatures with added catalysts like lead to determine its purity. However, modern technology has moved beyond the need for this slightly destructive method. Currently The Assay Office utilises a state of the art system which uses x-ray fluorescence. This method is just as accurate as the traditional methods, whilst also being better for the environment, quicker, and cleaner.