Hallmarking

In the UK, precious metals are subject to hallmarking legislation above certain weights. Sterling Silver weighing above 7.78g, Gold and Palladium above 1g and Platinum above 0.5g must be hallmarked in order to be legally sold.

As such, Frances Greenwood Jewellery is registered with Sheffield Assay Office where she sends her jewellery (when it is above the required weights) to be hallmarked. You can identify Frances' Hallmark as an FB in an oval. Example below-

For more information on precious metals and hallmarking, please watch the video below-