All precious metals used for jewellery by UK Law (The Hallmarking Act of 1973) must be hallmarked. The stamps have changed slightly over the years, but it still required to be marked with an Assay Office mark, Standard mark and a Sponsors mark. All other marks are either obsolete or optional. Jewellery items made before 1950 are exempt.
Sponsors Mark: one or more initials of the person or company wishing to present the piece for hallmarking. This does not have to be the ‘manufacturer’. The sponsor accepts all responsibility for piece.
Makers Mark: The ‘manufacturer’ of a piece. More prevalent pre 1720 as it then became the norm to use initials, rather than the then used monograms or symbols.
Date Mark: Used to help establish the year of manufacture. Today it can also simply be the year the piece was hallmarked. Not a statutory mark.
Standard Mark: Carat stamp (375/750/916 etc).
Import Mark: Used between 1904 and 1998. What was considered a useful mark by many, the import mark still showed which city the item had been hallmarked in, but a slight variation of the city’s mark showed the item had been imported from elsewhere.
Control Mark: Known as the ‘convention mark’. Brought in to control the standard of gold coming in to the UK from abroad. A ‘minimum’ control mark is used to stamp the item whilst in a pre-finished condition. It can then be hallmarked to UK standard.
Assay Office Mark: Today there are only 4 Assay Offices left in the UK: Birmingham, London, Sheffield, and Edinburgh.
Each an individual business, but part of the “British Hallmarking Council”, Birmingham is known to be the largest and busiest Assay Office in the world. Having moved premises only 3 times in its long history, 2015 has seen them move to a purpose built modern building to continue their sterling work in conjunction with not only the Jewellery Quarter, but the rest of the jewellers in the UK.
In times gone past, there were also offices in: Chester, Dublin, Exeter, Glasgow, Newcastle and York.
Special Marks: Most recent marks are the Millennium Mark (2000), Queen’s Golden Jubilee (2002) and Queen’s Diamond Jubilee (2012). Other occasionally seen marks are Queen Elizabeth II’s Coronation Mark (1953) and Queen’s Jubilee (1977).