18K gold (750)
The metal is 18-karat gold: 18 parts in 24 are pure gold, 750 in every 1,000.
How to read it
The UK’s Hallmarking Act says 18 carats indicates gold of 750 parts per thousand, and 750 is the figure its hallmark strikes for that standard, so 18K and 750 name the same gold.
Also searched as: 18K, 18 karat, 18KT, 750.
A stamp is a claim about the metal, made by whoever struck it. This page says what each mark means under the rules that define it; it doesn’t test or value anything.
An old British mark for 18 carat
William Chaffers’s history of hallmarks records a 1798 statute under which gold of this standard was marked with a crown and the figures 18, instead of the lion passant used until then. The crown is still one of the Act’s marks for gold.
More jewellery marks
Sources
- Hallmarking Act 1973, Schedule 1, Hallmarking Act 1973 (c. 43), Sch. 1, Pt. III, legislation.gov.uk (The National Archives), Sch. 1, Pt. III, para. 2
- Hallmarking Act 1973, Schedule 2: Approved Hallmarks, Hallmarking Act 1973 (c. 43), Sch. 2, legislation.gov.uk (The National Archives), Sch. 2, Pt. I, para. 2
- Hall Marks on Gold & Silver Plate (Chaffers, 1922), William Chaffers, Hall Marks on Gold & Silver Plate, 1922 edition, Internet Archive (scan), Statutes, 1798
Last reviewed September 27, 2026 by Rory Hansen. How we research