Fineness Hallmark

The fineness hallmark — also simply hallmark — is the single most important mark on bars, coins and jewellery made of precious metal. It states what share of the total weight is pure metal, and so forms the basis for every melt value calculation and for the legal classification of a piece as VAT-exempt investment gold.

Where the hallmark comes from

Marking silver and gold goods reaches back to the Middle Ages. English goldsmiths were required from 1300 to bring their work for testing to Goldsmiths' Hall in London — the origin of the word hallmark. Ireland has its own long tradition: the Assay Office of Dublin, established in 1637 and still operating from Dublin Castle, is among the oldest assay offices in the world and applies a distinctive set of Irish marks, including the crowned harp for gold.

Today the Vienna Hallmarking Convention (International Convention on the Control and Marking of Articles of Precious Metals, 1972) provides a shared Common Control Mark for its member states. Ireland operates its own statutory hallmarking regime under Irish law, administered by the Assay Office of Dublin, alongside recognition of the convention mark.

How fineness is expressed

The hallmark follows a thousandths scale (‰). In jewellery, the older carat notation for gold also survives:

For silver the common marks are 999, 925 (sterling silver), 835 and 800; for platinum, 950 and 999 dominate.

What else appears in the mark

A full hallmark set typically contains several elements:

1. Fineness figure — e.g. "750" for 18-carat gold
2. Sponsor's/maker's mark — the initials or logo of the refinery or manufacturer
3. Assay office mark — a symbol identifying the office that tested the article (the Dublin harp in Ireland)
4. Date letter or mint mark — for coins, the so-called mint mark
5. Serial number — often laser-engraved on certified bars

On LBMA Good Delivery bars (400-ounce gold bars) the individual serial number of the bar is additionally required.

Significance when buying and selling

For a dealer or refinery buying metal in, the fineness hallmark is the first checkpoint. If it is missing or looks tampered with, the achievable buying price drops sharply — and in case of doubt the dealer will demand an independent assay (streak test, X-ray fluorescence). With the current gold price and the stamped fineness, the material value can be worked out to the second.

For the VAT exemption on investment gold, EU rules (transposed into the VAT Consolidation Act 2010 in Ireland) require a minimum fineness of 995 ‰ for gold bars. Coins and bars without such proof cannot be traded as VAT-exempt investment gold.

Note: The tax and legal classification of individual products should be confirmed with a tax adviser in case of doubt — this text is not tax or investment advice.

Authenticity checks beyond the hallmark

The hallmark alone is no proof of authenticity. Professional testers always combine it with further methods:

• Weight and dimension checks (coin weight checker, coin size checker)
• Density method after Archimedes
• X-ray fluorescence analysis (XRF) — non-destructive, highly precise
• Ultrasound — reveals tungsten inserts in bars
• Online authenticity check — quick orientation against reference data

In brief

The fineness hallmark is the core legal record of any precious-metal piece: it names the purity, allows the material value to be calculated and decides the tax treatment. Anyone buying, selling or inheriting bars or jewellery should know the hallmark and, in case of doubt, have it confirmed by an independent assay.