Hallmark Guide

A Guide to Hallmarks in British Jewellery

Hallmarks are the backbone of trust in British jewellery. These small stamps confirm metal purity, origin, and year of testing. Once you understand them, you can read a piece of jewellery in the same way a historian reads a document.

What Are Hallmarks and Why They Matter

British hallmarking is one of the strictest systems in the world. When you see a legal hallmark on a piece of jewellery, it means the metal has been tested and verified by an independent Assay Office. You are not relying on guesswork or a seller’s opinion. For gold, silver, platinum, or palladium, a hallmark is the legal guarantee that the metal is what it claims to be.

For vintage and antique jewellery, hallmarks are especially helpful. They allow you to identify the metal, place of testing, and often the year, which all feed into value and authenticity.

The Four Parts of a British Hallmark

A full British hallmark usually includes four main elements. Not every piece will show all four, especially older or imported items, but this is the structure you are looking for.

1. Maker’s Mark

The maker’s mark identifies the person or company that submitted the piece for hallmarking. It is usually formed of initials inside a shaped outline. This can be useful for tracing the origin or workshop.

2. Metal Fineness Mark

This shows the metal purity as a number of parts per thousand. For example, 375 for nine carat gold, 585 for fourteen carat, 750 for eighteen carat, and 925 for sterling silver. This is the core stamp for value.

3. Assay Office Mark

This identifies which British Assay Office tested and marked the piece. London, Birmingham, Sheffield, and Edinburgh each have their own distinct symbol.

4. Date Letter

A single letter, in a particular font and shaped shield, that corresponds to a specific year. Each Assay Office runs its own date letter cycle, so the letter must be checked against the correct chart.

British Assay Offices and Their Symbols

British hallmarking is carried out by four Assay Offices. Their symbols often appear alongside the fineness mark:

London

Symbol: Leopard’s Head

Birmingham

Symbol: Anchor

Sheffield

Symbol: Rose

Edinburgh

Symbol: Castle

Gold and Silver Hallmarks: What to Watch For

Gold Jewellery

Gold jewellery in the UK should carry a fineness number. Common marks include:

  • 375 – nine carat
  • 585 – fourteen carat (often non-UK origin)
  • 750 – eighteen carat

Older pieces may also carry a traditional crown mark. Numbers such as 333 are not used in British hallmarking, so that usually indicates European origin rather than UK.

Silver Jewellery

Sterling silver is usually marked 925. On antique items you may also see the lion passant, the traditional symbol for sterling silver.

The key is consistency. A lion passant with an Assay Office mark that does not match the period, or a mix of symbols that do not belong together, can indicate later work, altered pieces, or mis-stamped items.

How to Read a Date Letter Correctly

Date letters cause more confusion than anything else. The letter itself is only part of the story. You also need to look at the font style and the outline that surrounds it.

  • The same letter in a different shield shape usually means a different year.
  • Serif and non-serif letters represent different cycles.
  • Each Assay Office runs its own date letter cycle.

To date a piece accurately, match the entire impression to a reliable chart for the correct Assay Office. Guesswork here can move an item by several decades.

Common Mistakes When Reading Hallmarks

Style vs Age

Assuming a piece is antique just because the design looks old. Style can be copied. Hallmarks give the solid evidence.

Logos vs Hallmarks

Mistaking a manufacturer’s logo or decorative stamp for a hallmark. True hallmarks follow a clear system and structure.

Numbers Without Context

Trusting any number stamped into metal as proof of gold or silver. Without an Assay Office mark, you do not have the same protection.

Ignoring Wear

Hallmarks can soften with decades of wear. A missing detail does not always mean it was never there, but heavy wear can make reading difficult.

Mismatched Combinations

Mixing symbols from different offices or periods. If the marks do not logically belong together, treat the piece with caution.

Using Hallmarks When You Buy Jewellery

When you look at a vintage or antique piece, use this simple checklist:

  • Find the fineness mark and confirm the metal purity.
  • Identify the Assay Office symbol.
  • Use a reliable date letter chart for the correct Assay Office.
  • Check that all marks look consistent in depth and angle.
  • Make sure the combination of marks makes sense for the period.
  • If anything looks wrong or forced, pause before you buy.

Hallmarks turn jewellery into something you can authenticate rather than guess at. They reveal the story behind the piece and allow you to judge age and value with far more confidence.

If you would like help understanding the hallmarks on a piece you own or are thinking of buying, you are welcome to get in touch.

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