The Mum’s Guide to Hallmarks: Spotting Real Gold at Home

The Mum’s Guide to Hallmarks: Spotting Real Gold at Home

Whether you are looking to sell some unwanted gold jewellery, or just having a sort out of the jewellery box, it can often be tricky spotting the real stuff from the plated. If you gold earring or bracelet was made after 1975 in the UK, it is mandatory the piece carries a set of standard hallmarks. Any gold jewellery made prior to this may still carry a simple purity marking. Learning to read a UK hallmark is the quickest way to separate treasure from trinkets, without the need for any sophisticated testing. All you will need is a good light, and potentially a jewellers loupe or magnifying glass. Grab a cuppa and let’s decode them together.

Why hallmarks matter (and why they’re teeny-tiny)

The current UK hallmarking system provides an independent guarantee of metal purity. It tells you what the piece is made from, where it was assayed (tested), and who it was tested by. In the UK, precious-metal items above 1g in weight must, by law, carry an approved hallmark before they can be advertised and described as gold, silver, platinum or palladium. Hallmarks are usually very small and are located out of sight, usually on clasps or inner bands. 

When shopping for heavier chains such as a gold Cuban link chain, inspect the clasp or the small flat tag near it for the millesimal fineness number (for example 585 for 14ct or 750 for 18ct) and the assay office mark to confirm authenticity.

Hallmark 101 – the five mini-clues to look for

Most modern UK gold can carry up to five marks, usually in a neat row:

1. Sponsor’s (Maker’s) Mark – the registered initials inside a tiny shield.
2. Traditional Fineness Symbol – a little crown for gold (optional but common).
3. Millesimal Fineness – the number that tells purity (e.g., 375, 585, 750).
4. Assay Office Mark – leopard’s head (London), anchor (Birmingham), rose (Sheffield) or castle (Edinburgh).
5. Date Letter – a changing font/shape that pins down the exact year.

If you spot at least marks 2 to 4 from the above list in the same line, you’ve likely got genuine gold.

Decoding the fineness numbers at a glance

Fineness	Carat	What it means in plain English
375	9ct	“Everyday” UK gold 37.5 % pure
585	14ct	Common in mainland Europe & US pieces
750	18ct	Classic engagement-ring quality
916	22ct	Deep yellow, often Asian wedding gold
999	24ct	Near-pure, too soft for most jewellery

Pro tip: the shape around the number has meaning too, a rounded rectangle (octagon) always signals gold.

Know your assay office (a fun history nugget for the Cheshire mums!)

Most new British made jewellery is hallmarked by one of the four designated assay offices in the UK; London, Birmingham, Sheffield or Edinburgh. Older pieces can carry the wheat-sheaves & sword emblem of the Chester Assay Office, which closed in 1962. Chester assayed pieces can carry additional value for collectors and precious metal enthusiasts.

A missing hallmark isn’t always a red flag

UK law exempts hallmarking for items under 1 gram. So tiny jump rings, fine chains, and earring backs may be genuine but unstamped. Antique gold pieces may also be absent of hallmarks when the regulations and laws on hallmarking were not as strict. You may also find hallmarks may have worn away after years of wear, this is commonly seen on the inside of wedding bands, where consistent contact with the skin is made. It’s also important to note, if your gold jewellery was bought international, hallmarks may not be present or unrecognisable.

Your DIY gold inspection kit

• Bright natural light (or a daylight lamp).
• Magnifying glass, phone macro lens, or jewellers loupe 5-10× magnification is plenty.
• Cotton cloth or soft tooth brush to clear away dirt so marks are clear.
• Hallmark cheat sheet – bookmark an online directory for instant symbol look-ups.

Step-by-step: Lay the jewellery piece flat under good lighting, locate the stamp (clasps and inside rings are common spots), magnify, then compare what you see to the table above. If you spot multiple hallmarks in a neat row, chances are you’ve struck gold, literally!

Still unsure? Ask a friendly expert

Hallmarks are tiny; even seasoned jewellers keep loupes on their keyrings. If your stamp is blurred, hidden by a repair, or you suspect plating, pop into a professional for confirmation. It’s always recommended to seek a professional opinion if you are unsure. Seeking help from a specialist gold buyer, or jeweller is essential to gain a definitive answer for those items you are unsure about.

Final thoughts

Reading hallmarks is a simple life skill when you are equipped with the right information. If you are looking to sell your gold, being prepared with the right knowledge can prevent you being under offered for your gold.

Happy hallmark hunting!

Guest Article.