Gold Assay
Carat Percent Gold Hallmark
24 100% gold N/A
22 92.2% gold 922
18 75% gold 750
14 58.5% gold 585
9 37.5% gold 375
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Assay Office Symbols
london assay office symbol London
Image of Edinburgh assay office Edinburgh
Birmingham Assay office symbol Birmingham
Sheffield Assay office symbol Sheffield
Hallmarks are the authorised stamp impressions that indicate maker, standard of fineness and the Assay office where the Hallmark was issued. Older hallmarks also include the year of manufacture, this is symbolised by a letter the font of which changes with every cycle of the alphabet. They are required by law if a piece of gold (9ct,14ct,18ct and 22ct) or platinum weighs more than 1 gram , 7 grams for silver. Any items requiring Hallmarking have to be sent to an Assay Office, allow three to five weeks for this process. We have the facility to process urgent hallmarks in one week - extra charges apply, please contact customer services for more information. (01268 546546)
Points to note, if a previous repair has been undertaken by using an inferior metal e.g. silver instead of white gold, the item will fail the assay
New items which we supply will of course require hallmarking.
Gold Hallmark Example
a diagram of a hallmark
Millesimal Fineness Mark - this is the number of parts per thousand of pure metal in the alloy. The current finenesses allowed in the UK are shown here.
finenesschart
Laser Hallmarks - these hallmarks are only burnt on to the surface of the metal by a laser they can be very faint. Rings that have laser hallmarks are harder to size as the hallmarks can easily be removed by the buffing and polishing that is necessary to size a ring correctly. We suggest you bring this to the attention of your customer before sending to the workshop for alteration. If the laser hallmark is removed it can be re-added for an approx. cost of £14.99. This will take a further 2-3 weeks as the ring will have to be sent to the Assay Office for remarking.