What is a hallmark and does all gold jewellery need one?

In the UK, it is a legal requirement that any gold jewellery being sold has an official hallmark from one of the four country’s Assay Offices. The hallmark is stamped on jewellery to certify the purity of gold, silver, platinum, or palladium and is applied after being thoroughly tested through the assaying process.

The main purpose of this is to provide consumer protection. With the high price of precious metals, lies a serious risk of fraud, where a thick plating of gold could easily cover a basic metal interior.

Even the most experienced jeweller or chemist can’t accurately calculate how much precious metal there is in an alloy by sight alone, so the UK’s Hallmarking laws protect the public and honest suppliers from those trying to deceive them. The UK’s Hallmarking Act 1973 makes it an offence for anyone in trade or business to:

1. Describe an un-hallmarked article as being wholly or partly made of gold, silver, platinum, or palladium.

2. Supply or offer to supply un-hallmarked articles to which such a description is applied.

Any jewellery being sold as gold, platinum, silver, or palladium needs to be sent to one of the Assay offices located in Birmingham, Edinburgh, London and Sheffield for verification. At these locations, the purity of the precious metals are tested through three different processes:

1. Sampling – The metal is sampled through non-destructive means using X-Ray Fluorescence Spectrometry machines.
2. Assaying – This spectrometry method is used on a random selection of samples and the results produced are extremely accurate.

3. Hallmarking – If the above tests don’t raise any red flags, then the hallmark is applied to the metal, certifying that it can be sold as a precious metal.

The UK is one of a few countries throughout the world that have made hallmarking compulsory. A rule which also applies to any items from overseas that are intended to be sold as a precious metal. The only time that this process isn’t necessary is if the metal being sold is under the legal weight threshold, which is 1 gram for gold.

Since 1998, there have been 3 compulsory marks that make up a hallmark, these include:

1. The unique mark of the person or company responsible for sending in the article.
2. The standard mark which highlights the fineness of the metal.
3. The assay office mark, confirming where the jewellery was tested and hallmarked.
4. Until 1998, it was compulsory to have the year in which the article was tested and marked, although this is now optional.