What Are Hallmarks In Jewellery? Decoding the Symbols on Your Favourite Pieces
- Kate Smith
- Mar 28
- 6 min read
Have you ever noticed tiny markings stamped inside a piece of jewellery?
These are known as hallmarks, and they're not just decorative - they're important symbols that tell a story about the metal’s purity, origin, and authenticity.
In the UK, hallmarking is a legal requirement for certain jewellery pieces, designed to make you feel more confident about what you're buying.
But what do these marks actually mean, why do they matter, and what should you be looking out for?
Discover everything you need to know about hallmarks in jewellery and prepare to become a hallmarking expert (or at least have some handy pub quiz trivia up your sleeve).
Hallmark definition - what does a hallmark mean in jewellery?
A hallmark is an official stamp applied to precious metal items to certify their content and quality.
In the UK, hallmarking is strictly regulated and it’s against the law to sell a precious metal item as ‘gold’ or ‘silver’ without a valid hallmark.
So, any piece of gold, silver, platinum, or palladium over a certain weight must be independently tested and stamped by an Assay Office - we have four of these in the UK.
Doing this prevents fraud and ensures you get exactly what you're paying for.
Jewellers will register with their local Assay Office and pay to have stamps made with their unique sponsor's mark.
We send pieces to our local Assay Office for hallmarking and pay per item, often in larger packages as it's more economical and efficient.
Understanding your jewellery: the components of a UK hallmark
A UK hallmark is made up of three compulsory symbols:
Assay Office mark
Each of the UK's four Assay Offices has its own unique symbol so you can instantly recognise which part of the country it was hallmarked in.
Without this, we can't legally sell jewellery claiming to be a certain precious metal here in the UK.
Here are the unique symbols of each UK Assay Office:
Birmingham Assay Office – the anchor
London Assay Office – the leopard’s head
Sheffield Assay Office – the Yorkshire rose
Edinburgh Assay Office – the castle.
Being based in Birmingham's Jewellery Quarter, our local Assay Office is just a leisurely stroll from our workshop.
Sponsor’s mark
A unique set of initials registered by the maker or brand, this tells you who submitted the piece for hallmarking. For example, our jewellery carries the ‘KS’ sponsor’s mark.
This stamp is created when a jeweller registers with its local Assay Office, and the process can be done by the jeweller or the Assay Office.
At Kate Smith Jewellery, we let the Assay Office do it.
Traditional fineness mark
This indicates the precious metal and metal content, for example:
375 for 9ct gold
750 for 18ct gold
925 for sterling silver
See the full list of precious metals and the number relating to them below.
In the UK, we mostly use 9ct and 18ct gold, but other countries (especially the USA and parts of Europe) frequently produce 14ct gold. So, if you come across a piece marked as 14ct, it’s likely from America or Europe rather than the UK.
This variation in standards is important when buying vintage or second-hand jewellery, as it helps you understand where a piece originated.
Date letter (optional)
Part of the UK hallmarking system, date letters indicate the year a piece was assayed.
Each year is represented by a specific letter in a unique font and shape, which changes annually in a 25-year cycle.
The exception is the letter J, because it can appear too similar to I in certain fonts, so is omitted to avoid confusion.
Fun Fact: Date letters date back to 1773!
Do you have piece that has a date letter? Check out this link to find out which year it was made.
Why is jewellery hallmarked?
Jewellery hallmarking isn’t just about law and regulation – it’s a matter of trust.
Under UK law, every hallmarked item has been rigorously tested to protect you from accidentally buying fake or lower-quality pieces.
Hallmarking is deeply connected to the history of the Jewellery Quarter and the wider industry, and the practice itself dates back as early as the 1200s, when Henry III made the first ever attempt to regulate goldsmiths in London.
Our local Assay Office is less than a 10-minute walk from our studio, and its strict processes ensure that only completed jewellery is marked, preventing any deception in the sale of precious metals.
So, we can't simply submit a piece of metal: they need to see the full item, or at least all components of it, for consumer protection.
The rules are different in other countries, so this is a huge bonus of buying from the UK - if you’re investing in quality pieces, you should know who made them and feel confident about their quality and authenticity.
Does all jewellery have hallmarks?
In the UK, hallmarking is only required for metals over a certain weight.
Minimum weight requirements for UK hallmarking
Gold – 1 gram or more
Silver – 7.78 grams or more
Platinum – 0.5 grams or more
Palladium – 1 gram or more
However, we choose to hallmark everything to avoid any confusion and give you extra peace of mind and assurance, even if there's no legal requirement for that particular piece.
We might have a pair of silver earrings that only weighs two grams, but they're still handcrafted, high-quality pieces, so we feel you deserve to have that piece hallmarked.
Hallmarking and remodelling jewellery
So, you may be wondering what the situation is when you have older pieces of jewellery remodelled into new pieces. How does that affect the hallmarking?
When remodelling old jewellery, different gold carats can be combined and a new hallmark will be added to the finished piece.
The new hallmark will always reflect the lowest gold content present in the piece.
For example, if a ring contains mostly 22ct gold but some 18ct has been introduced during the redesign, the final hallmark will be for 18ct gold.
The hallmarking process
To get a piece hallmarked, a jeweller must register with an Assay Office and pay to have a sponsor’s mark created.
They can choose to keep the stamp in their workshop to use themselves, or send pieces off to be marked at their local Assay Office.
How to read a hallmark (and what to do if you can’t make it out)
Hallmarks usually appear in a discreet position on your jewellery, like the inside of a ring band or the back of a pendant, for example.
They’re pretty tiny by nature, to avoid impacting the design, which can make them hard to decipher with the naked eye.
If you’re struggling to make out the symbols on your jewellery, a jeweller’s loupe will come in handy. These small magnifying tools are inexpensive and allow you to clearly see the details of your hallmark up close.
Of course, if you’re unsure about a hallmark on your jewellery and you want to understand its quality and origins, we’re always happy to help. Bring your piece to us, or send it in securely, and we’ll read the marks for you and explain what they mean so you know exactly what you have.
A guarantee of quality craftsmanship
Understanding how to check hallmarks ensures you invest in something authentic and valuable - essential when you’re spending a decent amount on a piece to cherish or gift to a loved one.
For more information, explore our guide to precious metals or jewellery remodelling services, or learn more about the history of hallmarking from the Assay Office website.
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