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Guide · hallmarks · sponsor · fineness · assay office

UK hallmarks,
explained.

Those tiny stamps inside a ring or under a spoon are a legal record. Read correctly, they tell you the metal, its purity, who made the piece and where it was tested. This guide shows you how to read all of them.

Three marks are compulsory. Sponsor, fineness and assay office — the rest are optional extras.

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Sponsor
Who made or
submitted it
Fineness
The metal and
its purity
Office
Where it was
tested and struck
Date
Optional letter
giving the year

What a hallmark is

A hallmark is an official set of marks struck into precious metal to guarantee its purity. In the United Kingdom, hallmarking is governed by the Hallmarking Act 1973 and carried out by independent assay offices, not by the maker. Because the testing is done by a third party, a hallmark is one of the oldest forms of consumer protection in Britain — proof, struck into the metal itself, that the item is what it claims to be.

It is an offence to describe an item as gold, silver, platinum or palladium in the course of trade without the correct hallmark, unless it falls under a weight exemption. That is why a hallmark carries weight when you come to value or sell a piece: it is independent evidence of the metal and its purity.

The three compulsory marks

Every current UK hallmark has three parts that must be present. Learn these three and you can read the essentials of almost any modern piece.

  • The sponsor's mark. A set of initials inside a shield, unique to the person or company that submitted the item for hallmarking. It identifies the maker or the firm, not the designer.
  • The fineness (purity) mark. A number showing how many parts per thousand are pure precious metal, inside a shield whose shape indicates the metal. This is the single most useful mark for valuation.
  • The assay office mark. A town symbol showing which of the UK's assay offices tested and struck the piece.

Reading the fineness number

The fineness, or millesimal, number tells you the purity in parts per thousand. The same system runs across all four precious metals, so once you know it you can read gold, silver, platinum and palladium alike.

MetalFineness marksIn everyday terms
Gold375, 585, 750, 916, 990, 9999, 14, 18, 22 and 24 carat
Silver800, 925, 958, 999925 is sterling, 958 is Britannia
Platinum850, 900, 950, 999950 is the usual jewellery standard
Palladium500, 950, 999950 is the common standard

For gold specifically, dividing the carat by 24 gives the fraction behind the number: 9 ÷ 24 is 0.375, hence 375; 18 carat is 0.750, hence 750. If you want to turn that purity into a metal value, our companion guide walks through the sum in how much is my gold worth.

The four UK assay offices

Four assay offices operate in the United Kingdom today, and each strikes its own town mark. The symbol tells you where a piece was tested — not necessarily where it was made or sold.

Assay officeTown mark
LondonA leopard's head
BirminghamAn anchor
SheffieldA rose
EdinburghA castle

On older pieces you may find marks from offices that have since closed, such as Chester (a shield of arms), Glasgow (a tree, bird, bell and fish) or Dublin (a crowned harp). A closed-office mark is a useful clue to age and can add interest to a piece.

The optional marks

Beyond the three compulsory marks, a hallmark may carry optional extras that add detail and character:

  • The date letter. A single letter in a distinctive font and shield that records the year of hallmarking. Now optional, but historically compulsory, so most antique pieces carry one — invaluable for dating.
  • Traditional fineness symbols. A lion passant (a walking lion) traditionally denotes sterling silver; a crown was long used for gold. These pictorial marks often sit alongside the number.
  • Commemorative marks. Special marks struck for events such as a coronation or jubilee in a given year.
  • Convention marks. A common control mark recognised across countries that signed the international hallmarking convention.

A hallmark confirms what a piece is, not what it is worth. Two identical-looking rings with the same fineness mark can differ hugely in value once maker, age and condition are taken into account. Read the marks first, then have the whole piece assessed.

When there is no hallmark

An absent hallmark does not always mean an item is not precious metal. Very light pieces are exempt: gold under one gram, silver under 7.78 grams, platinum under half a gram and palladium under one gram do not have to be marked. Some imported or antique pieces predate current rules, and marks can wear away with decades of use. If a piece is unmarked but you suspect it is gold or silver, it can still be tested — do not assume, and do not sell it as scrap without checking.

A quick checklist for reading your own pieces

  • Find the marks — usually inside a ring's band, on a clasp, or on the underside of silverware.
  • Use a loupe or magnifier; the marks are small and often worn.
  • Identify the fineness number first — it tells you the metal and purity.
  • Match the town symbol to one of the assay offices above.
  • Note any date letter and sponsor's mark, which help with age and maker.
  • If anything looks unusual or high-value, have it assessed rather than guessing.
Common questions

Reading the marks.

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What are the three compulsory marks in a UK hallmark?

A UK hallmark has three compulsory parts: the sponsor's mark, which identifies the maker or company that submitted the item; the fineness mark, a number showing the metal and its purity in parts per thousand; and the assay office mark, a town symbol showing which office tested and struck the piece. Together they confirm the metal has been independently tested and meets the stated standard.

What do the numbers in a hallmark mean?

The number is the millesimal fineness, the parts per thousand of pure precious metal. For gold, 375 is 9 carat, 585 is 14 carat, 750 is 18 carat and 916 is 22 carat. For silver, 925 is sterling and 958 is Britannia. Platinum is usually 950, and palladium commonly 950 as well. The higher the number, the more pure precious metal the piece contains.

What are the four UK assay office marks?

The four assay offices operating in the United Kingdom each have a town mark: London uses a leopard's head, Birmingham an anchor, Sheffield a rose, and Edinburgh a castle. The office mark on your item tells you where it was tested and hallmarked. Older pieces may carry marks from offices that have since closed, such as Chester, Glasgow or Dublin.

Does all jewellery have to be hallmarked?

In the UK it is an offence to describe an item as gold, silver, platinum or palladium without a hallmark, but there are weight exemptions for very light items. Gold under one gram, silver under 7.78 grams, platinum under 0.5 grams and palladium under one gram do not have to be marked. So a genuine gold piece may be unmarked simply because it is small, which is why testing still matters.

Does a hallmark tell me what my item is worth?

A hallmark confirms the metal and its purity, which is a key part of any valuation, but it does not set the value on its own. Weight, the live metal price, the maker, the age and the condition all matter, and a signed or antique piece can be worth far more than its metal. Treat the hallmark as reliable evidence of what the item is, then have the whole piece assessed.

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