How to register with a UK Assay Office for hallmarking

To legally sell items made of precious metals in the UK, you must register with one of the four UK Assay Offices and have your work hallmarked if it exceeds specific weight thresholds. Failure to do so is a criminal offence under the Hallmarking Act 1973, so securing your "Sponsor's Mark" is an essential step for any professional jeweller or silversmith.

1. Choose your Assay Office

There are four Assay Offices in the UK. While you can live anywhere and use any office, many makers choose the one closest to them or the one whose history aligns with their brand. Each office has a slightly different town mark:

• London (Goldsmiths' Company): A leopard's head.
• Birmingham: An anchor.
• Sheffield: A Yorkshire rose.
• Edinburgh: A castle.

2. Register as a "Sponsor"

In the world of hallmarking, you are known as the "Sponsor." To register, visit the website of your chosen office and complete their registration form. You will usually need to pay a registration fee (often for a 10-year period) and an annual renewal fee. You will also need to decide on your "Sponsor's Mark" design—typically your initials inside a specific shield shape.

3. Create your punch or go digital

Once your mark is approved, you need a way to apply it to your metal. You have two main options:

• Physical Punch: A steel tool used to strike the mark into the metal manually. The Assay Office can usually arrange for this to be made for you.
• Laser Marking: Most offices now offer laser hallmarking, which is ideal for delicate or finished pieces where a physical strike might cause damage. This removes the need for a physical punch tool.

4. Understand the weight thresholds

Not every single piece needs a hallmark. If your item weighs less than the following "legal thresholds," hallmarking is voluntary. If it weighs more, it must be hallmarked before you describe it as a precious metal in a commercial sale.

Precious Metal	Weight Threshold
Silver	7.78 grams
Gold	1.00 gram
Platinum	0.50 gram
Palladium	1.00 gram

5. Submit your work

Once registered, you send your items to the Assay Office (usually by Royal Mail Special Delivery). They will test the purity of the metal (assaying) and, if it passes, apply the hallmark. This consists of your Sponsor's Mark, the fineness mark (e.g., 925 for sterling silver), and the Town Mark of the office.

Tip: Always factor Assay Office turnaround times into your production schedule. During busy periods like Christmas, it can take two weeks or more to get your pieces back.

Best Practices

• Hallmarking Guidance Note: You are legally required to display a "Dealer's Notice" (available from the Assay Office website) on your premises or website to explain hallmarks to your customers.
• Mixed Metals: If you work with mixed metals (e.g., silver with gold accents), the rules get a bit more complex. Check the specific guidance on the Assay Office website to ensure you're marking the piece correctly.
• Keep Records: Track your hallmarking costs and postage, as these are legitimate business expenses.