Hallmarking Silver Clay UK

Hallmarking Silver Clay UK

Author : Michelle Williams

Is Silver Clay Real Silver?

One of the most frequent questions that I get asked on my Silver Clay Keepsake Jewellery, Fingerprint Jewellery,  Handprint Jewellery  and Artwork Jewellery Courses, is whether Silver Clay is real Silver and whether it can be hallmarked. The answer is yes!  It is real silver and can be hallmarked as such. 

Can Silver Clay be Hallmarked? 

Regular Art Clay Silver (999) is pure fine silver and can be hallmarked to authenticate that 999 parts out of 1000 are silver.  Art Clay Silver 950, is 95% silver and 5% copper and can therefore be hallmarked as 925 Sterling Silver.  Depending upon the type of Silver Clay that you use, once a piece of Silver Clay Jewellery is fired, it is either pure fine silver (999) or Sterling Silver (925) and can be hallmarked as such.
Should Silver Clay be Hallmarked? 
If you are in the UK, legally, you are required to get your Silver Clay Jewellery Hallmarked if you trade and describe it as Silver and it weighs over 7.78g.  Anything under that weight howeveris exempt and therefore does not legally have to be hallmarked.  However, many of my students prefer to hallmark as it adds authenticity and credibility to their work.  But, if your Silver Jewellery pieces are less than 7.78g in weight you are not required to do so. 

Is it illegal to Sell Silver Clay Jewellery without a Hallmark?

If the finished silver piece weighs more than 7.78gm it is a legal requirement to get it hallmarked if you trade and describe it as silver. This weight limit does not include stones, resin, or other non-silver parts.

Hallmark Exemptions

Exceptions to the Hallmarking rule include items made from precious metal, which fall below the minimum weight listed below:
  •  Silver – 7.78g
  • Gold – 1g
  • Palladium – 1g
  • Platinum – 0.5g

Can I Hallmark myself with a Silver or 999 Stamp? 

It is not legally binding to hallmark your own pieces. It must be done through an assay office. When you send your pieces in for hallmarking, they will be tested to confirm the material is what you say it is, and then hallmarked accordingly.

Where can I get my Silver Clay Jewellery Hallmarked?

There are four Assay Offices in the UK with whom you can register; London, Birmingham, Sheffield, and Edinburgh.They are all independent companies, so charges, processes and lead times may vary from office to office. It is worth carrying out some research and drawing up comparisons, to ensure you find the assay office with the best fit for your specific requirements. Whilst comparing fees, you should also consider asking:
  • What hallmarks are applied?
  • How long does the hallmarking process take?
  • How should you supply your pieces for hallmarking? 
  • Are there any packaging/un-packaging fees? 
  • How do they want the pieces marked up to illustrate where you would like the hallmark to go?

What is a Hallmark? 

A UK hallmark tells you what material/fineness the piece is, who made it, and where it was marked. It adds some authenticity to your jewellery, reassures your customers, and it allows you to be identified as the official maker of your creations. A complete Hallmark consists of three compulsory marks:
  1. Sponsor’s mark – (or Makers Mark) this is a unique mark which identifies who sent the piece in for hallmarking, i.e. “The Maker.”  This stamp usually consists of the maker’s initials or company name. 
  2. Standard (or Fineness) mark – this mark shows what material the pieces are made of and their fineness, in order to guarantee the type of precious metal used, along with it’s purity and authenticity. For silver clay this would usually be 999 (i.e. 99.9% pure silver) for fine silver clay Jewellery, or 925 (Sterling) for the sterling silver type clays.
  3. Assay Office mark – this symbol shows which office tested and marked the piece.

How does the Hallmarking Process Work?

There are several Assay Offices and they are all independent.  So, you need to select an Assay office to register with, who provides the best fit for your requirements. When you register you will get a unique Sponsor’s mark punch created for you, which is usually kept at the Assay Office.


How much does Hallmarking Cost?

It costs about £70 to register for ten years and the punch starts at about £120. You then send your jewellery to the Assay Office, where they test the purity of the metal. Once they have confirmed it is the material and fineness you have stated, they will then apply the hallmarks. The price of Hallmarking varies from office to office, but you usually pay a fee per batch sent in, with a minimum charge applied. There is also a fee for return postage and sometimes a handling charge. Rather then sending in individual items to be hallmarked, it is usually cheaper to send a batch and have several items hallmarked in one go.
For additional guidance, please read here: