A gold item in the UK will have a hallmark with at least 3 symbols.
The first mark will be a maker’s mark which can be any shape and typically has 2 or 3 letters indicating the company/who put the item into circulation for sale. This doesn’t necessarily mean it was the person who made the item.
The second mark will be a rectangular shape with the corners cut off, with one of the following numbers: 375, 585, 750, 916, 990 or 999. The number tells the precise metal content of the item expressed in parts per thousand.
Finally, the third mark will be one of four marks that shows which assay office applied the hallmark to the item. This will be a square chamfered mark, a square with the corners cut off, with either a lion’s head for London, an anchor for Birmingham, a rose for Sheffield or a castle for Edinburgh.
There are other optional marks that makers can request to be added. These are a traditional finesses symbol, date letter, commemorative marks such as the King’s Coronation and the Common Control Mark (CCM).
However, note that not all gold in the UK has to have a hallmark. Any item that weighs less than 1 gram is exempt from hallmarking, so lighter items might not carry a hallmark.