When it comes to jewellery hallmarks, distinguishing an individual mark can be confusing and laborious. Whether you’re buying a dramatic gold chain or a sparkling engagement ring and want to know its purity and value, or you're wanting to discover the history of a family heirloom, the hallmarks can tell you the story behind your precious metals.

Jewellery hallmarks have been part of UK law since 1973, meaning certain precious metals; silver, gold, platinum and palladium (since 2009), have to be stamped with individual marks each referring to a different metal. Yet, for the purpose of workability, wearability and durability, the precious metals stated are rarely used in their purest forms. There are five traditional Hallmarks; the assay office, the traditional fineness, the millesimal fineness, the sponsor and the date letter. 

In this blog post, we will discuss how you can understand hallmarked jewellery.


Assay Office 

The UK houses four assay offices, each is privately run and overseen by the British Hallmarking Council. This is where jewellery is tested, the metal is verified, and stamped appropriately. The assay offices are located across the UK in Birmingham, Edinburgh, London and Sheffield, and each location has a unique signature. As an Assay Assured Jewellery Retailer here at Hatton Jewellers, we ensure that all precious metals (within the weight exemptions) are independently tested and hallmarked.


UK Assay Office Hallmark Signatures

  • Birmingham - an anchor
  • Edinburgh - a castle
  • London - a leopard head
  • Sheffield - a rose


Fineness Mark

The traditional fineness mark and millesimal fineness mark reveals which precious metal the item is crafted from, however the traditional mark is now optional. Ultimately, the fineness of a precious metal refers to the weight of fine metal when taken in proportion to the total weight of a piece of jewellery. 


Millesimal Fineness Mark Signatures

  • Silver - oval shape

Sterling silver uses 92.5% pure silver in its composition, so consequently it’s hallmark number is 925. Whereas Britannia Silver uses 95.8% silver, making for a marking of 958.

  • Gold - rectangular shape 

Yellow, white and rose gold are commonly referred to in carat weights and a marking is made in relation to the purity. 9 carat gold translates to a marking of 375, 14 carat gold constitutes 585, and 18 carat gold of 750. 

  • Platinum - five sided shape.

Platinum products use 95% pure platinum in its composition, therefore it’s hallmarked 950.

  • Palladium - trapezium or three circles

With 50- 95% purity of metal, the hallmark for palladium is either 500 or 950. 


The individual who sends the items to the nearest assay office for testing, evaluation and hallmarking, must mark the metal in order for it to be identified. This mark could refer to the manufacturer, the importer, the wholesaler or the retailer. Usually the signature mark comes in the form of initials within a shape.


Year of Hallmarking

A second optional mark is the year of hallmarking. The date is denoted by a letter which could be upper or lowercase, varying in font and framed within a range of shapes. The font and shape determines the exact year in which the jewellery was hallmarked.


World Gemological Institute

From diamond earrings to enticing gemstone rings knowing that your precious stones are legitimate is of the utmost importance, therefore at Hatton Jewellers, we provide a certificate of authenticity alongside the official hallmark stamps. 

The World Gemological Institute identifies and evaluates all of our gemstones and diamonds, distinguishing whether or not they have been treated prior to purchase. This is performed by analysing the colour of a diamond, the cut of a diamond, the clarity (the absence of blemishes) and the diamond carat weight.


Have you had a look at your jewellery hallmarks? Let us know over on Facebook or Instagram.