Hallmarks: how to read the tiny stamps on precious metal
The tiny stamps on silver and gold record who stood behind a piece, how pure it is, where it was tested and often when. Here is how to read them.
Tool
Hallmark Decoder
Build a British hallmark mark by mark, or type a fineness number to find out what the metal is.
The four parts of a British hallmark
A British hallmark tells you who sent the piece for testing, how pure the metal is and where it was tested. The sponsor’s mark shows the initials of the maker or importer inside a shield. The fineness mark shows the purity in parts per thousand. The assay office mark names the office that tested it: a leopard’s head for London, an anchor for Birmingham, a rose for Sheffield and a castle for Edinburgh. The date letter, optional since 1999 but still widely used, changes every year.
Traditional pictorial marks may be added: a crown for gold, a lion passant for sterling silver, Britannia for Britannia silver and an orb for platinum. The builder above shows these symbols as simplified icons, not as the official punches.
Reading marks from other countries
Many countries use the same millesimal numbers without the other marks, so 750 on an Italian chain also means 18 karat gold. A number alone is the maker’s claim; a full hallmark from an independent assay office is a tested guarantee. Treat unfamiliar marks with curiosity and, for valuable pieces, ask an assay office or a qualified valuer.
Questions
Can I date a piece from the date letter?
Yes, if you know the assay office. Each office has published tables of its letters, which change in font, case and shield shape over the cycles. With the letter and the office mark together you can usually name the year of assay.
What does 925 mean?
It means 925 parts per thousand of silver, the standard called sterling silver. The remaining 75 parts are usually copper, which makes the metal hard enough for everyday use. Britannia silver, marked 958, is purer and softer.
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