UK Gold Hallmark Reference: Check Your Own Gold
Every genuine British gold hallmark is a short line of stamped symbols that, read together, tell you the purity, the office that tested it, and often the year. This is the practical reference: the tables you hold your own piece against. For the full explanation of how the system works, see our guide to the UK hallmarking system.
1. The gold fineness table
Fineness is stamped as a number in an oval, in parts per 1000, and it maps directly onto the carat scale. These are the UK legal standards for gold (Goldsmiths' Company Assay Office):
| Number you will see | Carat | Actual gold content |
|---|---|---|
| 999 | 24 carat | 99.9 per cent |
| 916 | 22 carat | 91.6 per cent |
| 750 | 18 carat | 75.0 per cent |
| 585 | 14 carat | 58.5 per cent |
| 375 | 9 carat | 37.5 per cent |
Two historic standards tell you the age at a glance: 15 carat (625) and 12 carat (500) were withdrawn in Britain in 1932, so a piece marked 625 or 15ct predates that year (BullionByPost).
2. The four assay office marks
The town mark tells you where the piece was tested. Four offices operate today (Assay Office London, Sheffield Assay Office):
| Office | Mark |
|---|---|
| London | A leopard's head (the oldest, the Goldsmiths' Company) |
| Birmingham | An anchor |
| Sheffield | A rose |
| Edinburgh | A three-towered castle |
Older pieces may carry the marks of offices that have since closed, including Chester, Glasgow, York, Exeter and Newcastle. Those marks help place a piece in time as well as location.
3. The traditional gold symbol: the crown
Alongside the millesimal number you may see a small crown. This is the traditional fineness symbol for gold. It is optional today rather than compulsory, but it is a useful confirmation that the metal is gold rather than another precious metal (Assay Office London).
4. The date letter, and how to date a piece
A single letter, in a particular font and shield shape, records the year the piece was hallmarked. The system began in London in 1478 (The Goldsmiths' Company). Two points make it usable:
- Each assay office runs its own cycles, and the same letter recurs every 20 to 26 years, so the letter alone is not enough. You need the letter together with its font and its shield shape, and the town mark, to fix the exact year.
- The date letter has not been compulsory since 1 January 1999, so a modern piece may not carry one.
To pin an exact year, match your letter against the official date-letter charts published by the assay offices: London, Birmingham, Sheffield and Edinburgh.
5. Reading it all together
Take your piece and a loupe. Find the line of marks, usually inside a ring's band, on a chain's clasp, or the edge of a brooch. Read in this order: the number for purity and proof it is gold, the town mark for where it was assayed, and the date letter, if present, for the year. A sponsor's mark (initials in a shield) will also be there, identifying who submitted it. Remember that a sponsor's mark is not itself a hallmark: the hallmark is the official fineness and town mark that the assay office applies.
Cross-referencing sponsor's marks
To identify the initials in a sponsor's mark, the assay offices and specialist databases hold searchable records. Start with the Birmingham and London assay offices, whose registers run back centuries.
Sources: the Goldsmiths' Company and its Assay Office (London); Sheffield, Birmingham and Edinburgh Assay Offices; BullionByPost. Full links throughout. If your gold is unmarked or foreign, it may still be genuine, it simply needs testing rather than reading, which is exactly what we do at Chapman Gold.