Buying gold or silver in Britain: what a hallmark is and how to check it

The UK's Hallmarking Act 1973 makes it illegal to sell an item described as gold, silver, platinum or palladium without an official mark — a hallmark. A hallmark is independent proof of the precious-metal content, tested by one of the country's four Assay Offices.

What a hallmark contains

There are three compulsory marks: the sponsor's or maker's mark (at least two letters in a surround — who made or submitted the item); the metal and fineness mark (a millesimal number showing purity in parts per thousand; the shape of the surround shows the metal); and the Assay Office mark (which office tested it — the UK has four: London, Birmingham, Sheffield, Edinburgh).

When a hallmark is NOT required

The law exempts light items — no hallmark is needed below these weights: gold under 1g, silver under 7.78g, platinum under 0.5g, palladium under 1g. The thresholds apply to items of a single precious metal at the minimum fineness; where base metal is also present, the weight counts the whole metal content.

What it means for a buyer

When buying gold or silver in Britain — in a shop or privately — look for the hallmark, especially if the item weighs more than the threshold. A missing hallmark on an above-threshold item sold as «gold» or «silver» is a red flag: by law it should be hallmarked.