Hallmark
Also: Assay mark, Fineness stamp, Test mark, Assay stamp
A hallmark is an official or trade test mark that permanently and tamper-resistantly certifies the fineness and origin of a precious metal item.
A hallmark is a struck or stamped mark on items made of gold, silver, platinum or palladium. It confirms officially, or through a recognised assayer, that the fineness of the metal corresponds to the stated value. In the United Kingdom this system is called hallmarking – the term derives from London's Goldsmiths' Hall, where precious metal goods have been tested since the 14th century.
Structure of a hallmarking system
A complete set of marks usually contains several individual symbols that together provide a seamless assay history:
| Mark | Meaning | Example (UK) |
|---|---|---|
| Fineness mark | Metal content in per mille or carat | 750 (18 carat gold) |
| Assay office mark | Identifies the assay office | Anchor (Birmingham) |
| Sponsor's mark / maker's mark | Registered initials of the submitter | Letter punch |
| Date letter | Year of assay (historical, partly discontinued) | A–Z per cycle |
| Optional additional marks | Jubilees, imported goods, CCM mark | Crown, orb |
The fineness mark is the most important element: it legally certifies how much pure metal the piece contains. The most common gold alloys used in UK jewellery are:
- 375‰ (9 carat) – lowest UK legal standard for "gold"
- 585‰ (14 carat) – widely sold jewellery standard
- 750‰ (18 carat) – high-quality jewellery and watch cases
- 916‰ (22 carat) – classic investment coins (Sovereign, Krugerrand)
- 999‰ – fine gold, investment coins and bars
International harmonisation
The Vienna Convention (CCM, 1972) allows member states to accept a uniform "Common Control Mark" – a balance mark with fineness statement. Goods bearing this mark may be sold without a further national assay. The roughly 20 members include Austria, Switzerland, Portugal, Finland and the United Kingdom, among others. The United Kingdom is a CCM member and recognises the Common Control Mark alongside its own hallmarks under the Hallmarking Act 1973.
For investment coins, the striking mint assumes the guarantee function of the hallmark: the Krugerrand bears no classic hallmark because the Rand Refinery, as a state-recognised refinery, itself vouches for the fineness.
Why hallmarks matter when buying
When buying jewellery, scrap gold or coins, the hallmark enables a quick initial assessment of the material value – even before a device such as an X-ray fluorescence analyser (XRF) is used. With the melt value calculator you can immediately determine the pure metal value on the basis of the read-off fineness.
If a hallmark is missing or appears to have been struck subsequently, caution is advised. A further authenticity check – for example by density measurement or ping test – provides clarity. The current gold price sets the reference value for the valuation.
Hallmarking obligation in the United Kingdom
In the United Kingdom, hallmarking is compulsory: it is a criminal offence under the Hallmarking Act 1973 to describe an un-hallmarked article as gold, silver, platinum or palladium in the course of trade, above the relevant weight exemptions (for example, gold articles below 1 gram). Hallmarking is carried out by one of the four UK Assay Offices (London, Birmingham, Sheffield and Edinburgh), which apply the statutory marks and thereby create trust in the stated fineness.
Other jurisdictions operate their own systems: some, such as Germany, have no compulsory hallmarking and rely on the maker's or dealer's civil-law responsibility for the fineness statement, while others (such as Austria) require mandatory hallmarking above certain weight thresholds.
In brief
Hallmarks are the oldest and most reliable system for controlling the fineness of precious metals – a small marking with great legal effect. Anyone valuing jewellery or broken gold reads the hallmark first and then calculates the material value.