Articles · Updated
Found an old chain, a ring or a pair of earrings at the back of a drawer and wondering whether it’s real gold? In the UK, the hallmark is your best clue – and a few simple home checks can help you sort the rest. This guide also explains, honestly, what those home checks can’t tell you.
Start with the hallmark
In the UK, gold is protected by law. Under the Hallmarking Act 1973, an item weighing 1 gram or more can only be sold or described as gold if it carries a hallmark from one of the UK’s assay offices. A full hallmark is made up of three compulsory marks, struck together:
A full UK hallmark, left to right
1. Sponsor’s mark
At least two initials in a shaped outline – the maker or company that sent the item for hallmarking.
2. Fineness mark
A number showing the gold content in parts per thousand, such as 375 for 9ct.
3. Assay office mark
A symbol showing which assay office independently tested and marked the piece.
You may also see optional marks, such as a date letter or a traditional symbol like the crown for gold.
The four UK assay office marks
London
Leopard’s head
Birmingham
Anchor
Sheffield
Rose
Edinburgh
Castle
Common gold fineness marks
| Mark | Carat | Pure gold |
|---|---|---|
| 375 | 9ct – the most common in the UK | 37.5% |
| 585 | 14ct | 58.5% |
| 750 | 18ct | 75% |
| 916 | 22ct | 91.6% |
| 999 | 24ct | 99.9% |
What each carat means for colour, durability and gold content is covered in our guide what do different carats mean.
No hallmark? Don’t rule it out
A missing hallmark doesn’t automatically mean an item is fake. Gold items under 1 gram – tiny stud earrings, thin chains, small charms – don’t have to be hallmarked at all. Marks also wear away over decades, or disappear when a ring is resized, and some older pieces made before 1950 can also be exempt. If you’re not sure what kinds of items are worth checking in the first place, see what items at home can contain gold.
Four home checks – and what they really tell you
These checks are safe and won’t damage your jewellery. They can help you rule things out, but none of them can prove an item is gold. Use the table below to read what you notice.
| Check | If you notice… | It may mean… | But remember |
|---|---|---|---|
| Magnet | The item clearly sticks | The core is probably another metal | Silver, brass and copper don’t stick either – and a clasp spring can stick on a real gold chain |
| Weight | A large piece feels surprisingly light | It may be hollow or plated | Hollow gold jewellery is still real gold |
| Colour | Patchy colour or two different tones | Possibly a worn plating | Gold can be yellow, white or rose – and 9ct can darken naturally |
| Worn spots | A silver- or copper-coloured metal showing through on edges or the clasp | Likely gold-plated | White gold is often rhodium-plated – a yellowish tone underneath is normal |
Why real 9ct gold can tarnish
You may have heard that real gold never darkens. That’s true of pure gold – but most jewellery in the UK is 9ct, which is only 37.5% gold. The other 62.5% is a mix of metals such as copper and silver, and over the years these can react with air, skin and household products. A 9ct chain with darker patches can therefore be completely genuine.
Solid gold or gold-plated?
Many gold-coloured pieces have only a thin layer of gold over another metal. Look out for these markings, which point to plating rather than solid gold:
Rolled gold
RGP
GF / gold filled
1/20
GP / gold plated
HGE
RGP
GF / gold filled
1/20
GP / gold plated
HGE
One UK twist: gold vermeil looks like gold but is gold-plated silver, so it is hallmarked as silver (925). If a yellow piece carries a 925 mark, it is silver underneath. For more on these terms and marks, see understanding gold and silver terminology.
Checks to avoid at home
Please don’t try these
The bite test
Jewellery gold is a hard alloy, and many soft metals mark too. You risk damaging the piece – and your teeth.
Scratching on a tile
It can leave a visible scratch, and the streak is hard to read reliably at home.
Acid test kits
Testing acids are corrosive and need training to use and interpret safely.
The flame test
Heat can damage stones, solder joints and the surface of the piece.
When to ask an expert
Home checks are great for sorting a drawer, but a proper test gives the final answer. It’s worth asking an expert about anything without a clear hallmark, inherited pieces with old or foreign marks, and items where your home checks gave mixed results.
Gold Arthur visits local stops across the UK. Your free, private valuation takes around 15 minutes, and everything is weighed and tested in front of you. The expert explains what they found and how any offer relates to the current gold market price. You can read the steps in what happens during a gold valuation.
Not every gold-coloured item contains gold, and not every item can be bought – but either way, you’ll leave knowing what you have. There is no obligation to sell. If you do decide to sell, you’re paid by bank transfer no later than the fifth banking day, never in cash.
Frequently asked questions
Can gold be real without a hallmark?
Yes. Items under 1 gram don’t need a hallmark, marks can wear away or be lost during resizing, and some older pieces are exempt. A test is the only reliable way to know.
What does 375 mean on gold?
375 is the fineness mark for 9ct gold: 375 parts per thousand, or 37.5%, is pure gold. It is the most common gold standard in UK jewellery.
Does real gold tarnish?
Pure gold doesn’t, but lower-carat gold can. 9ct gold contains 62.5% other metals, so slight darkening over time is normal and doesn’t mean the piece is fake.
Is the magnet test reliable?
Only partly. If an item sticks strongly, it probably isn’t solid gold. But plenty of non-gold metals don’t stick either, so passing the magnet test doesn’t prove anything.
Do I have to sell if I bring items for a valuation?
No. The valuation is free and there is no obligation to sell. You can take everything home and decide in your own time.
Sources
- GOV.UK: Hallmarking is the law – guidance summary
- Assay Office London: Hallmarking guidance notes
Checked 2 October 2026.
