Hallmarking

What is a Hallmark?

In the UK, a hallmark is a set of official marks applied to articles made of precious metals – gold, silver, platinum, or palladium – to certify their purity and authenticity. 

Hallmarking is a legal safeguard designed to protect consumers from fraud. It guarantees that an item has been independently tested and verified to meet all legal standards of metal purity (also known as fineness).

This is especially important when buying jewellery online, where customers can’t inspect items in person. A hallmark offers peace of mind and confidence that what you’re buying is genuinely what it claims to be.

Legal requirements

Under the Hallmarking Act 1973, it is a legal requirement for any item sold in the UK as gold, silver, platinum, or palladium to carry a recognised UK hallmark—if it exceeds certain minimum weights.

Because precious metals are typically alloyed with other metals to enhance their strength and appearance, it’s not possible to judge purity just by looking. That’s why hallmarking is so important—it ensures transparency and trust for both buyers and sellers.

Minimum weights requiring a Hallmark

Gold – over 1 gram

Silver – over 7.78 grams

Platinum – over 0.5 grams

Palladium – over 1 gram

Items below these thresholds do not legally require hallmarking, but many jewellers – including myself – choose to hallmark lighter pieces or at least add metal fineness and sponsor’s marks for added transparency.

The full UK Hallmark includes

Sponsor’s Mark – Identifies the individual or company who submitted the item for hallmarking.

Metal Fineness Mark – Indicates the precious metal and its purity.

Assay Office Mark – Shows which UK Assay Office tested and marked the item.

Date Letter – (Optional) Indicates the year the item was hallmarked.

The standard layout of a hallmark is horizontal, with minimal spacing between the component marks.