Put a 9 carat gold chain beside an 18 carat one. Same colour, same shine, same weight in the hand. One holds twice the gold of the other.
Nobody can tell them apart by looking. That includes us.
The four UK Assay Offices put it in one sentence in their own published guidance:
"It is not possible to detect by sight or by touch the platinum, gold, palladium or silver content of an item. It is therefore a legal requirement to hallmark all articles consisting of platinum, gold, palladium or silver (subject to certain exemptions) if they are to be described as such."
That is the whole of it. The law does not exist because gold is precious. It exists because gold is a liar. An alloy of 375 parts per thousand and an alloy of 750 parts per thousand look identical, wear identically and feel identical in the palm. Only a test tells you which is which, and a test you cannot see is worth nothing to you. So the mark goes on the metal, struck by somebody with no stake in the sale.
The requirement, stated plainly
Section 1(1) of the Hallmarking Act 1973 makes it a criminal offence for a person, in the course of a trade or business, to apply to an unhallmarked article "a description indicating that it is wholly or partly made of gold, silver, platinum or palladium", or to supply or offer to supply an article carrying such a description.
Three things follow from the wording, and they surprise most people.
The offence is the description, not the sale. Selling unmarked metal is not itself unlawful. Calling it gold is. And under section 1(7), exposing an article for supply counts as offering to supply it, so a live listing is enough. No money need change hands.
It applies to traders, not to the public. The words "in the course of a trade or business" are on the face of the Act. If you are selling your grandmother's chain, you are not committing an offence, whether it carries a mark or not. The burden of this law falls on us, not on you. That is deliberate, and it is right.
Saying so in the listing is not a defence. The exemptions in Schedule 1 are a closed list, and honesty is not on it. A dealer who writes "unmarked, believed 9ct" has still described it as gold. The law does not accept a disclaimer in place of a test, because a disclaimer is still only the seller's word.
Enforcement sits with Trading Standards, who have a statutory duty to enforce it under section 9(1), and with the British Hallmarking Council and the four assay offices, who may also enforce. On conviction on indictment, a description offence carries a fine or up to two years' imprisonment. Counterfeiting a hallmark or a die carries up to ten years. Under section 10, a court can order convicted stock delivered to an assay office. In practice it is the seizure that ends the business: in February 2026 a Camden market trader pleaded guilty to four breaches of the Act after more than 980 pieces of unhallmarked silver, valued at £106,050, were taken off the shelves.
What it is actually for
In November 2018 three people were jailed for a total of fourteen years at Birmingham Crown Court. Birmingham City Council's own account of the case describes the method: bangles infilled "with silver copper and other alloys" and finished with "a heavy gold plate", sold as 22 carat. When Trading Standards had them tested by the Birmingham Assay Office, some "could only be hallmarked at no more than 14 carat". The operation ran more than five years, made as much as £1 million, and sold "to other unsuspecting jewellers, as well as via eBay".
Read that last part twice. The people fooled were not only the public. They were jewellers, holding the piece, in the trade. That is how good a plated surface is at telling you what you want to hear.
It is not confined to organised fraud. In November 2021 a jeweller in Southall pleaded guilty at Uxbridge Magistrates' Court to nineteen offences under the Act. One piece, sold as 22 carat, was 18 carat.
This is why the marks matter, and it is also why they are old. The first statute is from 1300, under Edward I: no goldsmith was to make any vessel or jewel of gold or silver "except it be of the true alloy", and the Guardians of the Craft went from shop to shop to test the work. By 1363 a maker's mark was required, so the responsible goldsmith could be named. By 1478 the assay had moved into Goldsmiths' Hall and a salaried assayer was employed, so the man doing the testing was not paid by the man being tested. It is probably from that Hall that the word "hallmark" comes. In 1757 Parliament made counterfeiting a hallmark a felony punishable by death (31 Geo. II c. 32). Today the maximum is ten years. It has never been treated as a small thing.
Sheffield Assay Office describes the purpose better than we could: "to protect the public against fraud and the trader against unfair competition". Both halves are true. An honest dealer who tests and marks his stock cannot compete on price with one who does not, unless the law makes them stand on the same ground.
Reading a British hallmark
A modern UK hallmark carries three compulsory marks.
The sponsor's mark. The registered mark of whoever submitted the article. Ours is EEC. Without a sponsor's mark, an article counts as unhallmarked under section 2(4), even if the other marks are present.
The assay office mark. Which of the four offices tested it: a leopard's head for London, an anchor for Birmingham, a rose for Sheffield, a castle for Edinburgh.
The fineness mark. The parts per thousand of precious metal, as a number. For gold: 375 (9 carat), 585 (14 carat), 750 (18 carat), 916 (22 carat), 990, 999. For silver: 800, 925, 958, 999.
There are also three optional marks, struck only on request. The traditional pictorial symbols, a crown for gold, a lion passant for sterling silver. The date letter, which gives the year of marking. And any additional mark the Council directs.
Those three have been optional since 1 January 1999, under the Hallmarking (Hallmarking Act Amendment) Regulations 1998. It is worth knowing, because it answers the question we get asked most: a modern piece with no crown and no date letter is not suspicious. It is normal. The sponsor simply did not ask for them.
If you want to date a mark, our Hallmark Identifier is free, needs no account, and will decode any British piece, not only ours. It tells you the office and the year. It does not certify that any particular seller is trading lawfully, and we would not want you to read it that way.
What is lawfully sold without a mark
Not everything must be hallmarked, and a page that told you otherwise would be wrong, as well as unfair to every honest antique dealer in the country.
Gold under 1 gram is exempt. The test is less than one gram of metal, so a piece weighing exactly 1.00g is not exempt, and on a stone-set piece it is the metal that counts, not the stones. For silver the threshold is 7.78g, for platinum 0.5g, for palladium 1g.
Gold articles made before 1950 are exempt, provided they assay at not less than 375 and have not been altered since 1950. That is Schedule 1, Part II, paragraph 10, as amended in 2007. Certain categories of pre-1975 gold work are exempt too, including filigree, and pieces so heavily engraved or so set with stones that they could not be marked without damage.
Here is the part that matters to you as a buyer. The exemption does not lower the standard, it moves the proof. An exempt piece must still genuinely be of minimum fineness, and if it is challenged, the seller has to prove it. An exemption a dealer cannot evidence is not an exemption at all. So when we sell a piece unmarked, we tell you which exemption applies and why, and we hold the weight and the test behind it.
The marks on our own stock
Most of the gold sold here needs nothing from us. It came into the world already hallmarked: a full British mark, struck when the piece was made, sometimes a century and more ago. We read those marks under the loupe, piece by piece, and record them in the listing.
A piece with no UK hallmark is a different matter. However sure we are of the metal, the Act does not permit us to describe it as gold, so we do not. We are a registered sponsor at the Birmingham Assay Office, under the mark EEC, and stock that needs marking goes there to be assayed and struck before it is listed. The British Hallmarking Council calls the result "an independent third-party guarantee of precious metal fineness". The only exceptions are the exempt pieces described above, sold with the exemption stated and the evidence held.
We learned the sharp edge of this rule ourselves. Three Italian-made chains were listed here as gold on the strength of their factory 375 marks. Italian marks are not UK hallmarks. We took the listings down, sent the chains to Birmingham, and relisted them once they carried British marks.
We also display a Dealer's Notice, linked at the foot of every page: a requirement under section 11 for anyone dealing in precious metal articles. The Act speaks of "premises"; the British Hallmarking Council's view is that for an online business the premises are the website, so the notice lives here.
Gold is worth what it is worth because of what it is made of, and what it is made of is the one thing the eye cannot see. Hallmarking is the law's answer, and ours: every piece described as gold on this site carries either an assay office's mark or a stated, evidenced exemption. Compliance is the duty. Certainty is the point: ours in what we buy, and yours in what you take home.
This page is a plain English summary of the Hallmarking Act 1973, written for buyers. It is not legal advice, and no reliance should be placed on it for legal interpretation. The statutory text is at legislation.gov.uk; the definitive practical guidance is the UK Assay Offices' own Hallmarking Guidance Notes. If you are unsure about a piece, any of the four assay offices will help. Last checked: 28 August 2026.