Reference
Understanding UK Gold Hallmarks (and What Each Carat Is Worth)
A hallmark is a legal guarantee of purity. Once you can read one, valuing an item becomes straightforward.
The three compulsory marks
- Sponsor's mark — who submitted the item.
- Fineness mark — purity in parts per thousand: 375 (9ct), 585 (14ct), 750 (18ct), 916 (22ct), 999 (24ct).
- Assay office — London (leopard's head), Birmingham (anchor), Sheffield (rose), Edinburgh (castle).
🏴 The Edinburgh castle markScottish pieces often carry the Edinburgh Assay Office's three-towered castle. Worth noting: metal-dealer licensing differs in Scotland (Air Weapons and Licensing (Scotland) Act 2015) from England & Wales (Scrap Metal Dealers Act 2013).
What each carat is worth
Value per gram = gold spot price ÷ 31.1035 × fineness. So 9ct is worth 0.375× the pure-gold gram price; 18ct is 0.750×. Our hallmark decoder shows the live per-gram value for every standard — updated from the current spot price, not a static chart.
Ready to value a specific piece? Open the gold calculator and add it by carat and weight.
All figures are estimates of melt value, never offers. Not financial or tax advice.