Hallmarks: what the marks inside your jewellery mean

In the UK a hallmark is not decoration, it is law. Professional Jeweller set the thresholds out plainly on 10 August 2022, in Rob Corder's piece How to spot fake jewellery: every silver item over 7.78g and every gold item over 1g must carry a full UK hallmark. Below those weights a full hallmark is not required, which is why a perfectly genuine little silver charm often carries no hallmark at all.

I have made jewellery by hand in London for 22 years, from a stall on Portobello Road to Liberty, Selfridges, Harvey Nichols and Harrods. In that time a great many pieces have been put on my bench with the same question attached. Is this real gold, and how would I know?

A stamp is not a hallmark

Most people have this the wrong way round. A hallmark is applied by an assay office, which tests the metal and certifies what it is. A stamp is applied by whoever made the piece, and nobody checks it. Professional Jeweller is blunt about the difference: marks such as 925 and 375 indicate purity, but "these stamps are not hallmarks and should not be taken as a guarantee of fineness". The same piece warns that a fake mark can look convincing from a distance, and tells you to check closely for spelling mistakes and for fonts that do not match. A loupe and daylight at a window will show you far more than a phone camera will.

The marks are small and they hide. On a ring they sit inside the band, which is why a resize should be done by someone who knows not to destroy them. On a necklace they are usually on a little tag by the clasp, or on the back of the pendant. If you are peering inside a ring anyway, our ring size guide is worth 2 minutes.

What the numbers mean

They are parts per 1,000. In A comprehensive guide to precious metals, published by The Jewellery Editor on 1 August 2016, Rachael Taylor sets out the common ones. Sterling silver is 925 parts silver per 1,000 and its mark sits inside an oval. 9ct gold is 375 parts gold per 1,000, inside an octagon. 24ct gold is 999. Gold must reach at least 375 parts to be hallmarked at all, so anything under that is not precious metal in the legal sense. Platinum runs 850, 900, 950 and 999, 950 being the most common, and its mark is shaped like the side of a house.

One line from that guide catches almost everybody out. Silver that has been plated with gold is still hallmarked as silver, because the gold is a surface rather than the piece. For that surface to be called vermeil, Taylor writes, the plating must be at least 2.5 microns thick. A vermeil piece and a solid gold piece can look identical in a photograph and are not the same object.

What the marks tell you about something you inherited

This is where it stops being trivia. If a ring has sat in a drawer for 20 years, the marks tell you the one thing that decides what can be done with it. Solid gold can be melted and used again. Plated silver cannot, because there is almost nothing there to reclaim. Stones come out of either one and go into something you will actually wear.

That is the whole of my Second Life service. Inherited rings, loose gemstones, old diamonds, broken chains and odd earrings are all remade by hand in my London studio. Send me a photograph and I will tell you what it could become and what it would cost. The estimate is free and there is no obligation. If a piece turns out to be plated rather than solid, or it is simply not worth remaking, recycling your old jewellery is the honest answer instead, and that comes with a free postage label and a £20 voucher.

Buying something whose metal you can be sure of

The piece I would point at first is the Special Date Initial Necklace, a roman numeral date with an initial beside it. It is £75 in sterling silver, £85 in gold vermeil or rose gold vermeil, and £600 in 14kt solid yellow or white gold, across 5 chain lengths from 14in to 22in. One design, three metals, three different things to own in 30 years, and the price is the only place that difference shows before you buy.

I notice that people who have just had an old piece remade buy differently afterwards. They stop asking what a thing costs today and start asking what will be left of it later. For a first engraved piece the Cloud Charm is £25 in sterling silver, £30 gold plated and £35 rose gold plated, and the rest of the charms and chains sit alongside it. The Block Letter Necklace is £65 in sterling silver on a rollo chain. At the other end, the Solid Gold Galore Bracelet is £270 in 14kt solid yellow or white gold, and every solid gold piece is gathered in one place.

The second life is the real one. If there is something in your drawer you cannot read the marks on, send me a photograph and I will tell you what you have. Anna Lou x.

Questions I get asked

Is a 925 stamp a hallmark?

No. Professional Jeweller is clear that stamps such as 925 and 375 indicate purity but are not hallmarks and should not be taken as a guarantee of fineness. A full UK hallmark is applied by an assay office that has tested the metal. A stamp is applied by the maker.

What does 375 mean on a ring?

375 parts gold per 1,000, which is 9ct gold. The Jewellery Editor's metals guide notes it is stamped inside an octagon. For comparison, 24ct is 999, and 925 inside an oval is sterling silver. If your ring is 9ct and you no longer wear it, the gold can be reused in a remade piece.

Why does my silver charm have no hallmark at all?

Probably because it is too light to need one. The legal threshold Professional Jeweller gives is 7.78g for silver and 1g for gold, and a small charm or a fine pair of studs can sit well under it. An unmarked piece is not automatically a fake, which is exactly why the other checks matter.