Hallmarks are a traditional part of British jewellery production and are an official mark of guaranteed metal content. The process dates back to the 1300’s when King Edward enacted a statute requiring that all silver articles must meet the sterling silver standard (92.5% pure silver) and must be assayed in this regard by 'guardians of the craft' who would then mark the item with a leopard's head.

Precious metals are rarely used in jewellery in their pure form and even an expert cannot tell how much valuable metal an article may contain, without testing it.

The Hallmarking Act 1973 was introduced to establish official guidelines, and requires that all precious metal articles offered for sale in the UK have a hallmark applied by an independent assay office to guarantee the precious metal content of the item.

The article will be tested (assayed) and then marked to an internationally recognised standard of fineness, shown in parts per thousand, such as 925 (Sterling Silver) or 750 (18ct Gold). The only exceptions are items which are light and fall under the exemption weight of 1gram. To sell anything that has not been hallmarked is illegal in the UK.

There are currently four UK Assay Offices who are permitted to apply the UK hallmark and they all work independently of one another. They are based in London, Edinburgh, Birmingham and Sheffield and are all very different organizations.

The British Hallmarking Council is a body created by the Hallmarking Act 1973 to supervise the activities of the four assay offices with regard to hallmarking and ensure there is adequate provision of hallmarking within the UK.

The Hallmarking Process

A Hallmark is made up of three compulsory symbols:

The Sponsor’s or Maker’s Mark: This indicates the maker or sponsor of the article. In the UK this mark consists of at least two letters within a shield. No two marks are the same.

Metal and fineness (purity) Mark: Indicates the precious metal content of the article and that it is not less than the fineness of the article indicated. The fineness is indicated by a millesimal number (parts per thousand) and the metal type is indicated by the shape of the surround.

Assay Office Mark: Indicates the particular Assay Office at which the article was tested and marked.

If you want to find out more about hallmarking visit these websites:

The Goldsmiths' Company Assay Office

British Hallmarking Council