A Complete Guide to British Hallmarks: How to Read the Marks on Gold and Silver Jewellery

Every piece of gold, silver, platinum or palladium jewellery legally sold in the UK above a certain weight must carry a hallmark — a set of tiny stamped symbols that tell you, with legal force, exactly what the metal is, who submitted it for testing, and where it was assayed. For buyers of preloved jewellery, hallmarks are the single most useful tool there is: a two-second glance through a loupe can confirm a piece is genuine 9ct gold, reveal that it was assayed in Birmingham in 1978, and expose a “gold” chain as plated brass. This guide teaches you to read them the way a dealer does.

Why British hallmarks are special

The UK has operated a legal hallmarking system for over 700 years — it's one of the earliest forms of consumer protection in the world, dating to 1300 under Edward I. Unlike many countries where fineness marks are applied by the manufacturer on trust, a British hallmark is applied by an independent assay office only after the metal has been tested. Under the Hallmarking Act 1973, it remains illegal to describe an unhallmarked item as gold, silver, platinum or palladium (above the exemption weights) when selling it in the UK.

The exemption weights are worth knowing: gold items under 1 gram, silver under 7.78 grams, platinum under 0.5 grams and palladium under 1 gram don't legally require a hallmark. This is why very light earrings and fine chains are sometimes unmarked yet perfectly genuine — and why, at Sparklier, we test unmarked pieces independently before we'll describe them as precious metal.

The three compulsory marks

Since 1999, a full UK hallmark consists of three compulsory symbols, usually struck in a neat row:

1. The sponsor's mark

Two or more letters inside a shield — the registered mark of the maker or the company that submitted the piece for assay. Thousands of sponsor's marks have been registered over the centuries, and on antique pieces they can identify the workshop precisely, which adds provenance and sometimes considerable value.

2. The fineness mark

A number giving the precious metal content in parts per thousand. This is the mark most buyers care about:

• 375 — 9ct gold (37.5% pure gold)
• 585 — 14ct gold
• 750 — 18ct gold
• 916 — 22ct gold
• 999 — fine gold
• 925 — sterling silver
• 958 — Britannia silver
• 950 — the most common platinum standard

The shape of the surround also signals the metal: gold fineness numbers sit in an octagonal shield, silver in an oval, platinum in a five-sided “house” shape.

3. The assay office mark

The symbol of the office that tested the piece. Four assay offices operate in the UK today:

• Leopard's head — London
• Anchor — Birmingham (our home town — the Birmingham Assay Office, founded 1773, sits at the edge of the Jewellery Quarter and remains one of the busiest in the world)
• Rose — Sheffield (Sheffield used a crown until 1975, so a crown office mark helps date older pieces)
• Castle — Edinburgh

You'll also meet marks from closed offices on antique jewellery: Chester (closed 1962), Glasgow (closed 1964) and others. Far from being a problem, a defunct office mark is a lovely dating clue — our 1953 Rolex Imperial Oyster carries Glasgow import marks that place it precisely in time and trade route.

Date letters: reading the year

Before 1999 a date letter was compulsory, and it remains the collector's favourite mark: a single letter whose font, case and shield shape identify the exact year of assay. Each office ran its own alphabetical cycles, changing the letter style each time the alphabet restarted — so the same letter “A” might mean different years in different styles or offices.

Because the cycles are office-specific, the honest answer is that nobody memorises them: dealers look them up. The assay offices publish date letter charts, and the pocket reference Bradbury's Book of Hallmarks has been the trade standard for a century. The practical method is: identify the assay office first, then match the letter's style and shield shape against that office's chart. When we list a piece as, say, “hallmarked London 1978” or “Birmingham 1982”, that's exactly the process our team has followed.

The traditional pictorial marks

Alongside the numbers, older (and many modern) pieces carry traditional symbols that are worth recognising on sight:

• Lion passant — the walking lion that has marked English sterling silver for centuries
• Crown — the traditional mark for gold on pieces assayed in England before 1999
• Britannia — the seated figure marking 958 silver
• Orb — platinum's traditional symbol

Import and convention marks

Jewellery made abroad but sold in Britain historically received distinct import marks, and today you'll also see the Common Control Mark of the International Hallmarking Convention — a fineness number inside a balance-scale design — which the UK recognises from fellow member countries. On vintage watches especially, import hallmarks are a rich seam of history: they tell you when a Swiss watch officially entered the British market, which is how a “Glasgow imported” gold Rolex gets its story.

What hallmarks can't tell you

A hallmark certifies the metal — not the gemstones, not the watch movement, and not overall condition. A genuine 375 mark says nothing about whether the “sapphire” above it is natural, synthetic or glass. That's why authentication of preloved jewellery is a layered job: hallmarks for the metal, gemmological inspection for the stones, serial and reference numbers for watches. It's the process every piece in our collection goes through before listing — you can read more about it on our FAQ page.

Red flags to watch for

• No hallmark on a heavy “gold” piece — over the exemption weight, a UK-sold gold item should be marked. Unmarked heavy pieces need independent testing before you pay gold prices.
• Marks that are too crisp on a “worn” antique — genuine wear affects marks and surfaces together.
• 9ct marked as “9K” alone with no assay office symbol — a maker's stamp, not a British hallmark. Common on imported pieces; fine, but it carries no legal guarantee.
• Rolled gold and plate marks — “RG”, “gold filled”, “1/20 12K GF” and similar mean a gold layer over base metal, not solid gold.

Try it yourself

The best way to learn hallmarks is with a loupe and a real piece in hand. Every item in our rings, necklaces and earrings collections lists its hallmarks in the description, and where the marks are photogenic we show them — so you can practise matching what you read here against real Birmingham anchors, London leopards and decades of date letters. And if you ever want a second pair of eyes on a mark, whether it's ours or a piece you've inherited, get in touch — reading hallmarks is one of our favourite parts of the job.

Further reading: our guide to identifying vintage jewellery covers the other authentication clues — clasps, cuts, patina and construction.