If you’ve ever looked closely inside a ring or along a gold chain, you’ve probably noticed a few tiny symbols stamped into the metal. Most people never think twice about them — but those little marks tell you everything you need to know about your jewellery’s authenticity, purity, and origin.
They’re called hallmarks, and in the UK they’re not just tradition — they’re the law. Every genuine gold, silver, platinum, or palladium piece sold in Britain must be tested and hallmarked by one of the official Assay Offices. It’s a guarantee that what you’re buying is the real deal, not just “gold-plated” or “gold-coloured.”
The problem? Most buyers don’t know what hallmarks actually mean — or how to read them. That’s why we’ve created this simple guide: to help you understand exactly what you’re looking at the next time you buy or inspect a piece of jewellery.
By the end, you’ll know how to spot a genuine hallmark, what each symbol means, and why it matters so much — whether you’re buying new, second-hand, or vintage.
👉 Every piece at Blackwell Jewellers is fully hallmarked and verified by UK Assay Offices — browse our certified Jewellery today.
“Those tiny marks are your jewellery’s fingerprint — proof of its quality and origin.”
What Is a Hallmark?
A hallmark is an official mark stamped onto a piece of jewellery to prove the metal’s purity and authenticity.
It’s the oldest form of consumer protection still in use today — and in the UK, it’s a legal requirement for precious metals like gold, silver, platinum, and palladium.
When a jeweller creates or sells a piece made from these metals, it must be independently tested by an official Assay Office before it can be legally sold. Only once it passes that test is it stamped with its hallmark — a permanent mark guaranteeing that the metal content is exactly what’s claimed.
It’s important to know that a hallmark is not the same as a simple “stamp” you might see on imported or unverified pieces. A hallmark is verified by law; a stamp can be added by anyone.
In short, a hallmark is your proof of trust. It tells you your jewellery is genuine, made of the correct metal purity, and backed by independent testing.
👉 Every item at Blackwell Jewellers is fully UK hallmarked and independently verified for quality — shop our Jewellery Collection today.
“A true hallmark is a legal guarantee — not just a stamp.”
The 4 Main Parts of a UK Hallmark
Every hallmark tells a story. In the UK, an official hallmark usually contains four key symbols, each one revealing something different about your jewellery’s history and authenticity.
Here’s what to look for:
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Sponsor’s Mark (or Maker’s Mark)
This identifies the company or individual who submitted the piece for testing. It’s usually made up of initials inside a simple shape — for example, “BJ” for Blackwell Jewellers. -
Fineness Mark
This number tells you the purity of the metal. -
Gold: 375 (9ct), 585 (14ct), 750 (18ct)
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Silver: 925 (Sterling)
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Platinum: 950
The higher the number, the purer the metal. -
Assay Office Mark
This symbol shows where the metal was tested and hallmarked. -
London (Leopard’s Head)
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Birmingham (Anchor)
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Sheffield (Rose)
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Edinburgh (Castle)
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Date Letter (Optional)
Some pieces include a letter to indicate the year it was hallmarked. This is especially useful for vintage or antique jewellery collectors.
Together, these symbols guarantee that the piece is genuine, independently tested, and legally approved for sale in the UK.
👉 Want to see real examples? Browse our fully hallmarked Jewellery Collection at Blackwell Jewellers.
“Each hallmark symbol tells a different part of your jewellery’s story.”
Why Hallmarks Matter
Hallmarks aren’t just tiny symbols — they’re your guarantee of quality and protection.
When you buy hallmarked jewellery, you know exactly what you’re getting. It’s not about guesswork or sales talk — it’s verified proof that the piece is made from genuine precious metal, tested by an independent authority, and legally approved for sale in the UK.
Without a hallmark, there’s no way to be sure what you’re buying. A piece stamped “9ct” or “18ct” without an official hallmark could contain less gold than claimed — or none at all. Unfortunately, this is becoming more common with imported or unverified jewellery sold online.
A hallmark protects both the buyer and the jeweller. It builds trust, preserves resale value, and gives peace of mind that your jewellery is authentic. That’s why every single piece we sell at Blackwell Jewellers — whether brand new, second-hand, or bespoke — is properly hallmarked and certified.
It’s one of those small details that separates a professional jeweller from everyone else.
👉 Browse our Jewellery Collection today and shop with total confidence.
“A hallmark is more than a mark — it’s your legal proof of quality.”
How to Check and Verify Hallmarks
Once you know what to look for, checking a hallmark is easy — and it’s one of the smartest habits any jewellery buyer can develop.
Start by looking for a set of small stamped symbols on the inside of a ring band, the clasp of a chain, or the back of a pendant. Use a magnifying glass if needed. You should see a combination of letters, numbers, and tiny pictures — these are your hallmark symbols.
To verify what each mark means, visit the Assay Office’s online guide (for example, The Goldsmiths’ Company Assay Office). There you’ll find full charts showing every current and historic UK hallmark, including the four main components: sponsor, fineness, assay office, and date letter.
Be wary of pieces that only have one simple “stamp” such as “18K” or “925” — that’s not a legal UK hallmark. True hallmarks are applied only after the metal has been officially tested.
If you’re unsure, a professional jeweller can confirm authenticity in minutes.
👉 Every piece at Blackwell Jewellers is fully hallmarked and verified by UK Assay Offices — explore our Jewellery Collection today.
“A real hallmark has four symbols — and proof to back them up.”
Small Marks, Big Meaning
Those tiny stamps inside your jewellery might not look like much, but they carry a huge amount of trust. In the UK, a hallmark isn’t decoration — it’s proof. Proof that your jewellery is genuine, tested, and made to last.
When you understand what hallmarks mean, you instantly become a smarter buyer. You’ll know how to spot real gold and silver, how to avoid fake or mis-sold items, and how to protect your investment for the future. It’s knowledge that saves you money and builds confidence every time you buy.
At Blackwell Jewellers, we believe transparency matters. That’s why every piece we sell — whether it’s a simple gold chain or a diamond engagement ring — is fully hallmarked, verified, and certified by one of the UK’s official Assay Offices. It’s our promise that you’re always getting real precious metal, real craftsmanship, and real value.
👉 Next time you shop, look for the hallmark — or better yet, shop where it’s guaranteed.
Browse our Jewellery Collection today and see the difference that genuine quality makes
“Hallmarks are the signature of quality — small marks that make a big difference.”
