If you've ever turned a ring over in your fingers and noticed a tiny set of numbers stamped on the inside of the band, you're not alone in wondering what they mean.
A 375 hallmark is one of the most common marks you'll find on gold jewellery in the UK — and once you know what it tells you, you'll start spotting it everywhere.
It Means the Piece is 9ct Gold
The number 375 refers to the gold's purity, expressed in parts per thousand. A piece stamped 375 contains 375 parts pure gold out of 1,000 — or 37.5%.
In the UK, we refer to this as 9 carat gold, or 9ct.
The remaining 62.5% is made up of other metals — typically silver, copper, zinc or palladium — added to give the gold strength and durability. Pure gold, at 24ct, is actually quite soft. It bends, scratches and wears down easily, which is why it's rarely used in everyday jewellery on its own.
9ct gold strikes a balance between genuine gold content, wearability and price — which is why it's been a staple of British jewellery for well over a century.
| Hallmark | Gold Purity | Carat |
|---|---|---|
| 375 | 37.5% | 9ct |
| 585 | 58.5% | 14ct |
| 750 | 75.0% | 18ct |
| 916 | 91.6% | 22ct |
| 999 | 99.9% | 24ct |
Of these hallmarks, 375 and 750 are among the most commonly encountered on jewellery sold throughout the UK, while 916 is more often associated with jewellery originating from India, the Middle East and parts of Asia.
Is It Real Gold?
Yes, absolutely.
Despite having a lower gold content than 18ct or 22ct, a 375 hallmark confirms the piece has been independently tested and certified as genuine gold. In the UK, hallmarking is a legal requirement for gold jewellery above a certain weight, and it's carried out by one of four official assay offices — in London, Birmingham, Sheffield or Edinburgh.
If it carries a UK hallmark, it's been verified.
How Much is 375 Gold Worth?
The short answer is: it depends.
The hallmark tells you what the gold is. It doesn't tell you what the piece is worth — and the two things can be quite different.
Weight is the starting point. A heavier ring contains more gold and will always have a higher melt value than a lighter one with the same 375 stamp. Current gold prices matter too; the spot price of gold fluctuates daily, so the value of any piece moves with the market.
But precious metal value is only part of the picture.
A diamond solitaire in a 9ct gold setting may be worth many times its gold weight alone. An antique or pre-loved item of jewellery from a known maker, or jewellery with a designer or branded provenance, can command a significant premium over its raw material value. Two rings carrying an identical 375 hallmark can have dramatically different values once age, craftsmanship and stones are taken into account.
This is something we see regularly when customers bring in inherited jewellery. A piece that looks modest at first glance sometimes turns out to be far more significant — and the reverse can also be true.
If you're trying to understand the value of something you've inherited, our advice is always to consider the jewellery as a complete piece, not just the sum of its metal content. A professional assessment looks at everything: the gold, the stones, the maker, the condition and the market for that particular style.
What Does 9ct Gold Actually Look Like?
9ct gold comes in several colours, and they can all carry the same 375 stamp.
Yellow gold is the most traditional — a warm, rich tone produced by combining gold with silver and copper. It's the classic choice for wedding rings and everyday pieces.
White gold has a cooler, silvery appearance. It's made by alloying gold with white metals such as palladium, and is usually finished with rhodium plating to enhance the brightness.
Rose gold has become increasingly popular over the past decade or so. The distinctive pink tone comes from a higher copper content in the alloy mix, which gives it a warmth that complements a wide range of skin tones.
Three ring mounts, illustrating the colours of white gold, yellow gold and rose gold
Where Will You Find the Hallmark?
Hallmarks are deliberately placed somewhere discreet. On rings, look inside the band. On necklaces and bracelets, check near the clasp. On pendants, look at the bale — the small loop the chain threads through. Lockets and charms usually carry the mark inside or on the reverse.
Older and antique pieces sometimes have very small stamps that are difficult to read without a loupe or magnifying glass. If you're unsure, any qualified jeweller can check for you.
In addition, items of gold from overseas can often show markings unrelated to UK Assay Offices. For example, a 375 Gold stamp appears on this Italian gold cross.
Italian gold cross from Italy, showing 375 Gold stamp and international symbols, with Unoaerre italian manufacturer symbol.
Other Marks You Might See Alongside 375
The 375 is rarely the only mark on a piece.
You'll often see a small symbol indicating which assay office tested it — a leopard's head for London, an anchor for Birmingham, a rose for Sheffield, a castle for Edinburgh.
There may also be a sponsor's mark — the initials or symbol of the manufacturer or retailer who submitted the piece for hallmarking. And on older jewellery, a date letter can help pinpoint the year it was tested, which is particularly useful if you're trying to date an inherited piece.
Can Old 9ct Gold Be Remodelled?
Yes — and it's something we do regularly here at Serendipity Diamonds.
Inherited jewellery that doesn't suit your style, or pieces that have been sitting unworn for years, can often be transformed into something entirely new. The existing gold can be reused, and any diamonds or stones reset into a completely different design. Or, from time to time, we recreate worn, damaged or badly made jewellery designs, melting down the original ring.
It's one of the most meaningful ways to give old jewellery a new life.
Common Questions
Is 375 the same as 9ct gold? Yes — the two terms refer to exactly the same thing.
Does 9ct gold tarnish? The gold itself won't tarnish, but the alloy metals can occasionally cause slight discolouration over time. A gentle professional clean usually brings it straight back.
Is it suitable for everyday wear? Very much so. Its durability is one of the main reasons 9ct gold has always been popular for engagement rings, wedding bands and everyday jewellery.
Can a 375 hallmark be faked? Counterfeit hallmarks do exist, though they're uncommon. If you ever have any doubt about a piece, a jeweller can test it for you.
Serendipity Diamonds is an independent jewellery showroom on the Isle of Wight, specialising in diamond jewellery and handcrafted sea glass pieces. If you have questions about a piece of jewellery you've inherited or are thinking about remodelling something special, we're always happy to help.
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