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Hallmarking

Hallmarking at Hatton Garden Bespoke Jewellery

Every piece of precious metal jewellery sold by Hatton Garden Bespoke Jewellery is hallmarked by the London Assay Office in accordance with the Hallmarking Act 1973.

A hallmark is your independent assurance that the precious metal content of a piece of jewellery has been tested and certified. It is the oldest form of UK consumer protection, dating back to 1300.

What a hallmark tells you

A UK hallmark consists of three compulsory marks:

  • The sponsor’s mark: identifies the person or company that submitted the item for hallmarking.
  • The metal and fineness mark: indicates the precious metal (gold, silver, platinum, or palladium) and its purity, expressed in parts per thousand.
  • The assay office mark: identifies which of the UK’s four assay offices tested the piece. Our jewellery is tested by the London Assay Office, represented by a leopard’s head.

Many pieces also carry a date letter (identifying the year of hallmarking) and a traditional fineness mark (such as the crown for gold or the Britannia figure for 958 silver).

Exemptions

Under the Hallmarking Act, items below the legal minimum weight are exempt from hallmarking:

  • Gold: under 1 gram
  • Silver: under 7.78 grams
  • Platinum: under 0.5 grams
  • Palladium: under 1 gram

Where a piece is exempt, we will describe it as such.

Bespoke and custom commissions

All bespoke pieces finished by hand at our Hatton Garden workshop are fully hallmarked before delivery, unless they fall below the legal weight threshold. You will receive your piece with the hallmark already applied, alongside any accompanying certification (such as GIA or IGI diamond certificates for the stones).

The Dealer’s Notice

The British Hallmarking Council requires all retailers of precious metal jewellery to display the official Dealer’s Notice, which explains the approved hallmarks in use in the UK.

British Hallmarking Council Dealer's Notice: the official chart of approved UK hallmarks, showing the compulsory sponsor's mark, metal and fineness mark and assay office mark for gold, silver, platinum and palladium

Questions

If you have any questions about the hallmarking of your piece, or would like to see the sponsor’s mark registered to our workshop, please contact us: