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UK hallmarks basics
A hallmark is a set of small marks struck on precious metal to show who sent it for testing, what the metal is, where it was tested, and sometimes the year. This guide covers the basics.
What a hallmark is
In the UK, hallmarking applies to gold, silver, platinum and palladium, according to the Assay Office London. An independent assay office tests the metal and marks it. A hallmark is not a guarantee that an item is old or valuable. It is a guarantee of the metal's purity at the time of testing. For antique buyers, hallmarks are one of the most useful clues to date and origin.
The traditional hallmark: five marks
The Assay Office London describes a full traditional hallmark as five marks:
- Sponsor's mark (compulsory). Two to five initials inside a shield. It identifies the registered person or company responsible for submitting the item. It "establishes responsibility rather than identifying the manufacturer".
- Traditional fineness mark (optional). A symbol for the metal, such as sterling silver, Britannia silver, gold, palladium or platinum.
- Millesimal fineness mark (compulsory). Required since 1999. It shows the purity in parts per thousand, such as 925 for sterling silver. The shield shape shows the metal. Items are marked to the lowest precious metal standard present.
- Assay office mark (compulsory). Shows which office tested the item. London uses the leopard's head. Birmingham, Sheffield and Edinburgh have their own marks.
- Date letter (non-compulsory). Changes each year on 1 January. The font, case and shield shape also change, so each letter corresponds to one year. Date punches are destroyed at the year's end.
The Convention mark
A Convention hallmark has four marks: the sponsor's mark, the common control mark, the millesimal fineness mark and the assay office mark. It lets items be sold between member countries without being tested again. The recognised finenesses on the Assay Office London page are:
| Metal | Fineness marks |
|---|---|
| Gold | 375, 585, 750, 916, 999 |
| Silver | 800, 925, 999 |
| Platinum | 850, 900, 950, 999 |
| Palladium | 500, 950, 999 |
How to read a mark in practice
- Use good light and a loupe. Marks are small.
- Find the sponsor's mark first, then the assay office mark. The office mark tells you where it was tested.
- If there is a date letter, compare it with a date-letter chart for that office. Letters repeat in cycles, so the font and shield shape matter.
- Check that the marks are crisp and in a line. Cut-and-pasted marks or marks that look soldered on are red flags; see spotting reproductions.
Older silver and unmarked items
Older British silver may carry marks that predate the current system. Some very old items, items from other countries and certain small items may not be marked. Absence of a mark does not prove a fake, but you should ask why. Items from overseas follow that country's rules. For anything valuable, ask a specialist.
Why hallmarks matter when you buy
If a stallholder says an item is sterling silver, the hallmark is how you check. A full set of crisp marks is reassuring. Missing marks need an explanation, and a mark does not tell you the item is antique, because modern silver is hallmarked too. Look at style, weight, wear and the price in context with the marks.
Where to learn more
The Assay Office London page linked below shows the marks and has contact details if you want an expert. For general buying advice see buying tips, and when you are ready to sell, read selling antiques.
Frequently asked questions
What does 925 mean on silver?
It is the millesimal fineness mark for sterling silver: 925 parts silver per thousand.
Is the date letter compulsory?
No. The Assay Office London says the date letter is non-compulsory, although it is traditional and very helpful for dating antiques.
Which metals are hallmarked in the UK?
Gold, silver, platinum and palladium.