How to read a UK hallmark

Gold basics 8 September 2026 2 min read

British hallmarking began in 1300 and is one of the oldest forms of consumer protection in the world. A hallmark shows that an independent assay office has tested the metal and that it is at least as pure as it claims to be.

Is hallmarking a legal requirement?

Yes. Under the Hallmarking Act 1973, it is an offence to describe an item as gold, silver, platinum or palladium in the UK unless it is hallmarked, or exempt by weight. For gold, the exemption applies to items under 1 gram. Every usgoldapp piece over that weight carries a full UK hallmark.

The three compulsory marks

1

Sponsor’s (maker’s) mark

A set of at least two initials inside a shield. It identifies the company that submitted the piece for hallmarking and is responsible for it.

2

Millesimal fineness mark

A number showing purity in parts per thousand, such as 375, 585, 750, 916 or 999 for gold. Each precious metal has its own shield shape around the number, so the outline tells you the metal at a glance.

3

Assay office mark

Shows which of the four UK assay offices tested the piece: a leopard’s head for London, an anchor for Birmingham, a rose for Sheffield and a castle for Edinburgh.

Optional marks

  • Date letter: a letter in a shield showing the year of hallmarking. Collectors love these for dating antiques.
  • Traditional fineness symbol: a crown for gold, a Britannia figure or lion for silver.
  • Common Control Mark (CCM): an international convention mark recognised in member countries.
Close-up of a gold ring
On rings, the hallmark is usually stamped or laser-marked inside the band.

Where to find it

Look inside ring shanks, on the clasp or the tag beside it on chains and bracelets, and on the post or back of earrings. On delicate pieces, assay offices often use a laser mark, which is crisp but tiny. A 10× jeweller’s loupe makes it easy to read.

Red flags

  • Only a number such as “750” with no assay office mark. This is a manufacturer’s stamp, not a UK hallmark.
  • Letters such as “GP”, “GF”, “HGE” or “RGP”, which mean gold-plated or gold-filled rather than solid gold.
  • A seller describing a heavy piece as “gold” with no hallmark at all.

Unsure about a piece you own? Send us a clear photo through our contact form and our team will help you read the marks.

Care advice, personalised. Every piece is different. Add yours to the usgoldapp care planner and get a plan written for its metal, carat and stones in seconds.