Is a set of component marks applied to articles of the precious metals gold, silver, platinum or palladium.

Means that the article has been independently tested.

Guarantees that it conforms to all legal standards of purity (fineness).

Guarantees provenance by telling us where the piece was hallmarked, what the article is made from, and who sent the article for hallmarking.

The standard hallmark formation is horizontal with minimal spacing between the marks.

Other formations of these hallmarks, often called "bespoke" or "display marks" are available.

The UK has been a signatory to the The Convention on the Control and Marking of Articles of Precious Metals (known as the Hallmarking Convention) since its inception in 1972.

The Hallmarking Convention is an international treaty between Contracting States, which aims to eliminate trade barriers in the cross-border trade of precious metal articles.

This means that the Goldsmiths’ Company Assay Office can strike the Convention Hallmark which is recognized by all member countries in the International Convention. Conversely, articles bearing the Convention Hallmark (marked in Member states) are legally recognized in the UK and do not have to be re-hallmarked here.

Fineness’s recognized under the Convention are:


9K : 375

14K: 585

18K: 750

22K: 916

24K: 999

Platinum - 850, 900, 950, 999.

Palladium - 500, 950 and 999

For more information on hallmarking visit:


Mayru Gems

Mayru Gems
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