WHAT IS A JEWELLERY HALLMARK?
A hallmark is a set of marks showing that an item made from precious metal has been independently tested by an Assay Office. It confirms the type and fineness — or purity — of the metal.
In the UK, hallmarking is a legal requirement when gold, silver, platinum or palladium jewellery is sold above the relevant weight threshold. It provides reassurance because the precious-metal content cannot be confirmed accurately simply by looking at the finished piece.
A hallmark is more than a number such as 925 stamped into the metal. A complete UK hallmark contains three compulsory marks.
WHAT DO THE THREE COMPULSORY MARKS MEAN?
SPONSOR’S MARK
This is the unique mark registered by the person or business responsible for submitting the jewellery for hallmarking. It is sometimes casually called a maker’s mark, although it identifies the registered sponsor rather than necessarily proving who physically made every part of the item.
FINENESS MARK
This number shows the precious-metal content in parts per thousand.
Common examples include:
• 925 for sterling silver
• 375 for 9ct gold
• 750 for 18ct gold
The shape surrounding the number also helps identify the type of precious metal.
ASSAY OFFICE MARK
This identifies the Assay Office responsible for testing and hallmarking the jewellery.
The four UK Assay Offices use different symbols:
• London — leopard’s head
• Birmingham — anchor
• Sheffield — rose
• Edinburgh — castle
WHICH JEWELLERY MUST BE HALLMARKED?
UK law sets different exemption weights for each precious metal:
• Gold: 1 gram
• Silver: 7.78 grams
• Platinum: 0.5 gram
• Palladium: 1 gram
Items above these thresholds must carry a recognised hallmark if they are being sold and described as those precious metals.
A genuine item weighing less than the relevant threshold can legally be sold without a hallmark. Makers can also choose to have lighter pieces hallmarked voluntarily.
This means the absence of a hallmark doesn’t automatically prove that a piece is fake. Its weight, age, origin and any exemptions must also be considered.
WHAT ARE THE OPTIONAL MARKS?
You may find additional symbols alongside the three compulsory marks.
These can include a traditional fineness symbol, a date letter or a commemorative mark. The date letter shows the year in which the item was hallmarked, which may not always be the exact year it was originally designed or made.
Older jewellery may carry different styles of marks, while imported pieces can display recognised international or overseas hallmarks.
IS A 925 STAMP A COMPLETE HALLMARK?
No. The number 925 indicates that an item is claiming to be sterling silver, but a number on its own is not a complete UK hallmark.
Small items below the legal weight threshold may carry a manufacturer’s 925 stamp without being independently assayed. That doesn’t necessarily mean the item is poor quality, but the stamp alone doesn’t provide the same independent verification as a complete hallmark.
Unfortunately, numbers and symbols can also be applied to metal that doesn’t meet the claimed standard. If an item is above the legal threshold, look for the sponsor’s mark, fineness mark and Assay Office mark together.
WHAT DOES A HALLMARK NOT TELL YOU?
A hallmark verifies the precious metal, but it doesn’t tell you everything about the jewellery.
It doesn’t confirm:
• whether a diamond or gemstone is natural, laboratory-grown or an imitation
• the quality or value of a gemstone
• the standard of construction or finishing
• the identity of the individual who physically made every component
• the age of the piece unless a date letter or other evidence is present
• the jewellery’s current financial value
A hallmark is an important piece of information, but it should be considered alongside the condition, craftsmanship, gemstones and provenance of the jewellery.
HOW CAN YOU CHECK A HALLMARK?
Hallmarks are often tiny, so a jeweller’s loupe or magnifying glass can help.
Start by looking for the three compulsory elements: the sponsor’s mark, the numerical fineness mark and the Assay Office symbol. You can compare them with the official UK hallmarking guidance and Dealer’s Notice.
Remember that older, heavily worn, repaired or resized jewellery may have faint or incomplete marks. Some genuine pieces may also be exempt because of their weight.
If the marks look inconsistent, the seller cannot explain them or an item is being sold as precious metal without the hallmark you would expect, ask further questions before buying. A jeweller or Assay Office can provide more reliable guidance than home testing methods.
HOW MY JEWELLERY IS HALLMARKED
My sponsor’s mark is registered with the Goldsmiths’ Company Assay Office in London.
When a piece I make exceeds the legal weight threshold, it is submitted for independent testing and hallmarking. This stage is included within the timescale for a bespoke commission and confirms that the metal meets the required fineness standard.
Pieces below the exemption weight may not legally require a hallmark, although I will always explain the metal used and answer any questions about the marks on your jewellery.
DO YOU NEED HELP WITH A PIECE OF JEWELLERY?
If you own jewellery with marks you don’t understand, I can take an initial look as part of a repair or redesign enquiry. Where formal identification, valuation or specialist testing is needed, I’ll explain that and recommend the appropriate next step.
You can read more about my jewellery repairs and jewellery redesign services or get in touch if you would like to discuss a particular piece.
