Hallmarking in the UK

Hallmarking is required by law for all items containing 7.78g or more of silver (1g or more of gold).  My maker’s mark is registered at the London Assay Office at Goldsmiths’ Hall in London where it is lasered onto the silver piece.  Goldsmiths’ Hall is the first recorded place in the world to carry out assaying (testing) and hallmarking of precious metals over 700 years ago in the early 1300s.

A UK hallmark tells you what material/fineness the piece is, who made it, and where it was marked.

The Full Traditional Hallmark comprises five marks:

  • Sponsor’s or Maker’s  mark
  • Traditional fineness mark
  • Millesimal fineness mark
  • Assay Office mark
  • Date letter mark

The London Assay Office uses this five part Full Traditional Hallmark as standard.

What do the Symbols of the Full UK Hallmark Represent?

Sponsor’s Mark (also known as the Maker’s Mark)

This is the registered mark of the company or person that submitted the article for hallmarking. It is formed of initials of that person or company inside a shield shape. The shield shape varies, and a minimum of two initials must be included.  Each one is unique.  My mark is a three leaf clover with the initials GHR in it.

Traditional Fineness Symbol

The traditional fineness symbol is an optional part of the hallmark but applied as standard in the London Assay Office.  You will see the first symbol on my hallmarked pieces.

Millesimal Fineness Mark

This mark tells you how fine, or what quality, the metal is, as well as indicating the metal type. This numerical format was introduced in 1999 and shows the precious metal content of the article, expressed in parts per thousand.  The London Assay Office marks a piece to the lowest standard of alloy content, so it guarantees that the quality of the article is no less than the fineness indicated. 

The shape of the surrounding shield indicates metal type. In the Gold Fineness mark, 375 is 9 carat, 585 is 14 carat, 750 is 18 carat and 916 is 22 carat. In the Silver Fineness mark 925 is Sterling and 958 is Britannia Silver.

Assay Office Mark

This mark tells you which Assay Office tested and hallmarked the article. 

The historic image of the leopard’s head, the town mark for London, and the mark of the Goldsmiths’ Company Assay Office, continues to be internationally recognised as the stamp of approval and guarantee of quality from the renowned home of hallmarking.

The leopard’s head mark of London has been used by some of the finest craftsmen in history, on some of the most prestigious and celebrated works.

Date Letter Mark

A non-compulsory element, the date letter changes annually on January 1st. The font, case, and shield shape all change so each can only indicate one specific year.  All date punches are destroyed at the end of the year.  London Assay Office applies this mark as standard.

Information from www.assayofficelondon.co.uk/hallmarking/uk-hallmarks