Understanding British Jewellery Hallmarks

An Ingot pendant in 9ct gold, circa 1977, London hallmarks, 30gms. Sold for $1,062

An understanding of jewellery hallmarks is essential for specialists and collectors alike, as they offer valuable information as to the origin, date, and composition of a piece of jewellery or objet d’art. The British hallmarking system, which has ensured rigorous and high-quality standards over hundreds of years, has meant English pieces continue to be coveted by collectors worldwide. 

The hallmarking system as we know it today was established in 1327 when the Goldsmith’s company of London created a system of marks under the rule of Kind Edward I to regulate the purity of materials used in jewellery. These marks acted as a guarantee of quality and authenticity and an early version of consumer protection. Initially introduced as a rudimentary system of crude symbols, as the industry grew, the complexity of hallmarks developed to reflect the necessary changes in legislation. Hundreds of years and many changes later, the trade continues to be regulated through the Hallmarking Act of 1973.

A full traditional hallmark is composed of five marks – a Sponsor’s Mark, a Traditional Fineness Mark, a Millesimal Fineness Mark, an Assay Office Mark, and a Date Letter Mark. Only the Sponsor, Millesimal, and Assay Office marks are compulsory, so it is commonplace to find pieces with only three marks. 

Sponsor’s Mark

The Sponsor’s Mark is typically a combination of letters reflecting the individual craftsman or company responsible for making the piece and submitting it to be assayed (determining the content or quality). An individual or company can only obtain a Sponsor’s mark through registration with an Assay office and it has to be a minimum of two and a maximum of five letters.  


Traditional Fineness Mark

The Traditional Fineness Mark indicates the fineness of the metal through symbols. These include a crown for 18 / 22ct  gold, a lion for sterling silver, and Athena for palladium.


Millesimal Mark

Similar to the Traditional Fineness Mark, the Millesimal Mark indicates that the purity of the metal used in the construction of a piece conforms to legal standards, however this is expressed as parts per 1000. 18ct gold for example is 750 parts of 1000 and is stamped as ‘750’. 


Assay Office Mark

An Assay Office Mark identifies the Assay office responsible for testing and verifying the piece. The Assay offices were first established in seven major cities throughout Britain, the first being London (identified by the leopard head). The largest assay office in the world is based in Birmingham, identified by an anchor symbol. Today, the only remaining Assay offices are based in London, Birmingham, Sheffield, Edinburgh, and Dublin. 


Date Mark

Finally, a Date Mark indicates the year of manufacture.  First introduced in London in 1478 as protection against fraud by the assayer, this took the form of a letter of the alphabet. At the end of the alphabet, or every 26 years, the letter font was updated and a new cycle began. What initially began as further verification from the Assay office means that today, specialists can date pieces of jewellery with accuracy. The addition of date marks became optional in 1999, and as such more contemporary pieces may not have a reference to when the object was assayed.  

On jewellery, the marks are commonly arranged in a horizontal line, typically with Sponsor, Traditional Fineness, Millesimal, Assay Office, and Date Mark in order from left to right. Embodying a rich tradition spanning hundreds of years, British hallmarks continue to be respected internationally due to the rigorous high standards governed by the Assay offices. For specialists, collectors, and enthusiasts, hallmarks offer invaluable insight into the origin and history of a piece of jewellery. 

BETHANY MCGOUGAN /  Head of Fine Jewels & Timepieces

Banner Image: Die stamping hallmarks in a gold Assay office, London / Alamy

August 2023