GoldQuestions
Gold hallmarks explained
A UK gold hallmark is an official assay mark that verifies precious metal fineness, but it is most useful when read in context with weight, dimensions, paperwork, and product type.
Last reviewed: 2026-06-01
What a hallmark contains
A UK hallmark is stamped by an independent assay office after testing a precious metal item. A full hallmark can include the sponsor or maker mark, the fineness mark, the assay office mark, and sometimes a date letter. The system is especially relevant to jewellery, antique silver, and fabricated precious-metal items where the buyer cannot judge purity by appearance. For a UK reader, the important point is that hallmarking is a consumer-protection system, not a decorative detail. It tells you that a metal item has been tested to a stated standard by a recognised office, although the meaning still depends on the item, its age, and whether the mark is genuine.
Fineness marks
Fineness is shown in parts per thousand. This is more precise than everyday carat language and helps compare gold, silver, and mixed-metal items. A 750 mark means 750 parts per thousand gold, commonly described as 18 carat. A 916 mark is close to the fineness associated with 22 carat gold and is familiar to many UK buyers because of Sovereigns. A 999 mark means fine metal, but the same number can appear for gold or silver, so the wider product context matters. Fineness marks are useful because they convert vague language such as solid gold, high carat, or pure silver into a more specific metal-content claim.
| Mark | Metal | Fineness | Common name |
|---|---|---|---|
| 375 | Gold | 37.5 percent | 9 carat |
| 585 | Gold | 58.5 percent | 14 carat |
| 750 | Gold | 75.0 percent | 18 carat |
| 916 | Gold | 91.6 percent | 22 carat, Sovereign standard |
| 999 | Gold | 99.9 percent | Fine gold or 24 carat |
| 925 | Silver | 92.5 percent | Sterling silver |
| 999 | Silver | 99.9 percent | Fine silver |
UK assay office marks
The assay office mark identifies the office that tested and marked the item. The four active UK assay offices are London, Birmingham, Sheffield, and Edinburgh. Historic pieces can also carry marks from offices that are no longer active, which is why antique items often need more specialist interpretation. A mark should be read as a set, not as one isolated symbol. The sponsor mark, assay office mark, fineness mark, and any date or convention mark can work together to explain what the item is claiming to be. If one element looks wrong for the period, style, or stated origin, that is a reason to slow down and verify further.
| Symbol | Assay office |
|---|---|
| Leopard head | London, Goldsmiths Hall |
| Anchor | Birmingham |
| Rose | Sheffield |
| Castle | Edinburgh |
Bullion products work differently
Bullion coins from major national mints usually carry mint marks and official specifications rather than jewellery-style assay hallmarks. A Gold Britannia, for example, does not need a standard assay-office hallmark because its stated purity comes from The Royal Mint as issuer. Sovereigns, Krugerrands, Maples, Eagles, and other recognised bullion coins are normally checked against official weight, diameter, thickness, metal composition, and design details. Bars from major refiners carry refiner marks, serial numbers, assay cards, or packaging rather than the same marks used on jewellery. That means a buyer should not reject a bullion coin simply because it lacks a jewellery hallmark, but should know which verification route applies.
Fakes and limitations
A hallmark is useful evidence, not a complete guarantee. Marks can be counterfeited, applied to plated items, misread, damaged, or transferred into misleading settings. Valuable items should be checked using several signals: weight, dimensions, density, paperwork, seller history, dealer verification, and professional assay where appropriate. The risk is highest when a seller pressures for speed, refuses normal checks, gives vague provenance, or uses photos that do not clearly show the mark and the whole item. For jewellery, hallmarking is only one part of value as condition, gemstones, craftsmanship, brand, and resale route can also matter. For bullion, the better comparison is usually against mint or refiner specifications rather than jewellery rules.
Key points
A hallmark can identify fineness, assay office, and maker or sponsor. Bullion coins and bars are often verified through mint or refiner evidence instead. 750 means 18 carat gold, while 916 means 22 carat gold. A single mark should be read alongside the full item, its weight, its age, its dimensions, and its paperwork. Hallmarks can be fake or misleading, so high-value purchases deserve more than one authenticity check.
Educational disclaimer
This guide is educational only and is not financial, investment, tax, legal, or personal advice.
FAQs
Does every gold item need a hallmark in the UK?
Items described or sold as gold in a commercial context generally need hallmarking, with exemptions for some very small or antique items. Bullion coins from official mints use mint marks and specifications instead.
What does 750 on gold mean?
750 means the item contains 750 parts per thousand gold, or 75 percent gold content. It is commonly described as 18 carat gold.
What are the four UK assay offices?
The four active UK assay offices are London, Birmingham, Sheffield, and Edinburgh. Historic marks from closed offices can appear on antique pieces.
Why do Royal Mint coins not have standard hallmarks?
Minted bullion coins carry the mint guarantee, specifications, and marks rather than jewellery-style assay hallmarks. The hallmarking regime is mainly designed for jewellery and fabricated items.
Can a fake item have a real-looking hallmark?
Yes. Marks can be counterfeited or applied misleadingly, so readers should not rely on a hallmark alone for valuable items.