All of my pieces are hallmarked by the Birmingham Assay Office.

One of the requirements of the Hallmarking Act 1973 is that all dealers supplying precious metal jewellery (or other items made of precious metal) shall display a notice explaining the approved hallmarks (see below).

A hallmark is an official mark stamped on items made of precious metals (such as gold, silver, platinum, or palladium) to certify their purity and authenticity. It protects consumers by guaranteeing the metal content.

A full UK hallmark typically contains three parts:

The Sponsor’s Mark

Identifies the manufacturer, retailer, or maker who is responsible for submitting the item for testing.

The Fineness Mark

Shows the purity of the metal (e.g., 925 for sterling silver, 750 for 18ct gold).

The Assay Office Mark

Indicates which of the UK’s assay offices tested and hallmarked the item. The UK has several, including London, Birmingham, Sheffield, and Edinburgh.

Optional marks may also appear, such as a date letter (indicating the year it was hallmarked) or a traditional fineness symbol.

Hallmarking