Hallmarking and US

When it comes to jewellery, precious metals are rarely used in their purest form. Instead, they are usually alloyed with lesser metals to achieve a desired strength, durability and colour.

It isn’t possible to detect the precious metal content of a piece of jewellery by sight or touch. Therefore, it is a legal requirement for gold, palladium, platinum and silver pieces above a certain weight to be fully and independently hallmarked before they can be legally sold in the UK.

Hallmarks, by law, have to be applied to:

  • Gold pieces over 1 gram
  • Palladium pieces over 1 grams
  • Platinum pieces over 0.5 grams
  • Silver pieces over 7.78 grams

At Harriet Kelsall Bespoke Jewellery we always go above and beyond for our customers, which is why we choose to give a full, independently applied hallmark to every piece of customer jewellery that leaves our Hertfordshire workshop.

The stamp is always carried out externally by The UK Assay Office, who ‘assay’ (test) every piece of jewellery in the UK. We are registered with the London Assay Office and the Birmingham Assay Office, who check that it is the metal specified and ensure that all of our precious metal is compliant with the UK’s regulations. If it passes their internal confirmation process, it gets their stamp of approval in the form of a hallmark. This mark guarantees that your piece of jewellery has been independently tested for its quality, provenance and type of metal.

For any piece of jewellery that is below the UK hallmarking Act’s mandatory weight for hallmarking, we operate a separate due diligence process which involves periodic voluntary testing of items that fall below the mandatory weight to ensure they meet the minimum fineness requirement.

For any pieces of Ready To Wear jewellery that are below the mandatory weight for hallmarking under UK law, we operate a separate due diligence process. This involves us periodically testing the pieces to make sure that they meet the minimum fineness required.

Assay Assured

Assay Assured

This is the world’s only jewellery-specific digital Trustmark, backed by all four UK Assay Offices, where hallmarking takes place. This Trustmark ensures our online pieces meet the Assay Assured standards and that our pieces are hallmarked, and their precious metal content matches their description.


To explain it a little better, we’ve broken down the hallmark in our banner image for you here:

Our own ‘HK’ mark is stamped first, so this ring can be immediately recognised as having been made by us at Harriet Kelsall Bespoke Jewellery. Next, you have two markings that tell you more about the type of metal used in the piece. Whether it be gold, palladium, platinum, or silver each has it’s own identifiable stamp. This ring has a crown symbol, so we know it’s been made from solid gold. Palladium has the helm of the Greek goddess ‘Pallas Athena’ as its stamp, while platinum has an orb & cross and sterling silver has a lion passant.

Now we’ve identified the metal itself, we need to know it’s quality or ‘fineness’ which comes from the numerical figure alongside the crown in this instance. This figure measures the amount of precious metal in the ring in parts per thousand, which is why the number is so high! The ‘375’ stamp seen here is the figure for 9 carat gold; 18 carat gold in comparison is ‘750’ because there is a higher concentration of gold in the metal. Platinum and palladium are hallmarked at 950, while Sterling silver is hallmarked at 925.

Precious metals are often alloyed with other metals to improve their durability and alter their colours – i.e. white and rose gold. This is where a hallmark can really help, as you may not be able to identify the metal make-up of an alloyed metal so easily.

Each Assay Office in the UK has its own specific symbol so you can identify which of the four Offices this piece has been hallmarked at: London (a leopard’s head), Birmingham (an anchor), Sheffield (the Yorkshire rose) or Edinburgh (a castle). London’s leopard face is the stamp you will find on most of our pieces and is the oldest out of all of the Offices.

Usually at the very end of the hallmark, the letter represents which year the piece of jewellery has been stamped in, running in alphabetical order year to year, with the font changing to differentiate each decade. 2019 uses the letter ‘U’ so we can discern that this piece was stamped back in 2014.

In this instance, Fairtrade Gold has been used and so the very recognisable Fairtrade logo sits at the end of this hallmark, certifying that the gold used in this piece has been fairly paid for, responsibly sourced and mined. We were chosen by the Fairtrade Foundation as one of a group of the first 20 jewellers in the world to launch Fairtrade Gold and we worked extensively together with the Fairtrade Foundation on establishing the processes involved.

There are also commemorative hallmarks which are rarer, but can be seen on some older pieces – for example there are hallmarks from the 1953 Coronation and the Millennium in 2000. A recent commemorative hallmark was also introduced and designed for Her Majesty Queen Elizabeth II's Platinum Jubilee.

For more information on hallmarks, have a look at The Assay Office’s ‘Anatomy of a Hallmark’ here.

A brief history of the hallmark

Hallmarking has been around since the 14th century to regulate pieces made from silver and gold within the UK and protect consumers against fraud. The stamps have a rich and charming history, with many individual hallmarks having come and gone over the years!

During the Middle Ages hallmarking was regulated by local governments and was performed by assayers. In 1300, England saw the introduction of hallmarking for silver items by King Edward I which was instilled and carried out by 'guardians of the craft'. This later developed into a system which centred around the London Goldsmiths' Hall - giving its name to the term 'hall'marking.

It wasn't until 1973 that the various laws were simplified and brought together to form the blanket Act we use today - The 1973 Hallmarking Act. This Act is much more concise and easier to understand, while still retaining the tradition of the craft.

Hallmarking is a real positive about buying or commissioning a piece of jewellery from the UK, as the strict regulations give you a guarantee as a consumer that your piece of jewellery is exactly what it says it is.