I'm writing this guide having just bought a 'gold' bracelet in the UK from eBay described as 'fully hallmarked'. When the item arrived the only marking on the piece was "375", meaning it had 375 parts per 1000 of gold in its alloy and was equivalent to 9ct gold. (It is probably Italian).
This is not 'fully hallmarked', in fact it is not 'hallmarked' at all by one of the UK Assay Offices. Selling in the UK, this item cannot even legally be described as 'gold'.
It is worth noting that a scrap gold dealer will not pay full price for articles only marked by carat or parts per thousand.
A fully hallmarked item has to have the sponsor's mark, the fineness mark, the assay mark and until recently, a date letter.
For unregistered people, an Assay Office will fully Hallmark your piece for a very reasonable price. The Birmingham Assay Office has quoted me 10 GBP plus postage for marking my 'gold' 16 grm bracelet.
Also be aware that some people are selling metal stamps with "375" and higher marks on them and any unscrupulous seller could add these to a plated or rolled gold item.
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