A Short History of Silver Assaying and Hallmarks

Why silver needed policing

The hallmark is one of the oldest consumer protections in the world, and it exists because silver is easy to cheat with. Pure silver is too soft for most uses, so smiths alloy it with copper. Add a little more copper than declared and the piece looks and feels the same, but the maker pockets the difference.

No buyer could detect that by eye. So for more than two thousand years, societies have answered the same question: how do you prove what a piece of silver is made of, and how do you record that proof on the object itself? Assaying is the testing. Hallmarking is the record.

Ancient tests: the touchstone and the fire

The earliest assay was the touchstone, a fine-grained dark stone. Rub the metal across it, compare the streak with streaks from bars of known purity, and an experienced eye could estimate fineness. The Greeks knew it as the Lydian stone, after the kingdom that minted some of the first coins. It was quick and left the object intact, but it gave only an estimate.

The more rigorous method was fire. In cupellation, a sample is melted with lead in a porous bone-ash dish called a cupel. The lead oxidises, carries the base metals into the cupel, and leaves a bead of precious metal behind. Weigh the sample before and after, and you know its purity. Versions of this were in use in the ancient Near East and the Mediterranean, and it stayed the standard assay for centuries.

Marking came later. Silver plate from the Byzantine Empire, roughly the 4th to 7th centuries, carries official control stamps, an early sign that a state was willing to vouch for the metal in an object.

Medieval England: sterling and the leopard's head

The system most collectors know began in England. In 1238 Henry III ordered that silver wares be made to the same standard as the coinage: sterling, 92.5% pure silver. In 1300 Edward I went further, requiring that wares be tested by wardens of the goldsmiths' craft and struck with a leopard's head before sale.

The London goldsmiths received a royal charter in 1327 and became the Worshipful Company of Goldsmiths. Work was brought to their hall to be assayed and marked, which is where the word hallmark comes from: a mark struck at Goldsmiths' Hall. The leopard's head became the London town mark, and in modified form it still is.

Building the full hallmark

Over the next five centuries the single mark grew into a set, each added to solve a specific problem.

• Maker's mark (1363). A statute required each smith to have his own mark, so a substandard piece could be traced to the person who made it.
• Date letter (1478 in London). A letter changed each year identified when a piece was assayed, and so which warden was answerable for it.
• Lion passant (1544). Introduced during Henry VIII's debasement of the coinage, it came to signify sterling standard and was the core English mark for over 450 years.
• Britannia standard (1697–1720). Silversmiths were melting and clipping sterling coins for raw metal. Parliament raised the compulsory standard for wares to 95.8%, marked with Britannia and a lion's head erased, so plate could no longer be made from coin. Britannia silver remains a permitted higher standard today.
• Duty mark (1784–1890). The sovereign's head showed that tax on the piece had been paid.

Assay offices also spread beyond London. Provincial offices operated at various times in towns such as York, Exeter, Chester, Newcastle and Norwich, each with its own town mark. Scotland developed its own system from the 15th century, centred on Edinburgh. In 1773 Birmingham and Sheffield won their own offices, marked by an anchor and a crown; Sheffield's crown was replaced by a rose in 1975. Most offices closed over time. Four remain: London, Birmingham, Sheffield and Edinburgh.

Science and law in the modern era

For silver, the fire assay gave way to chemistry. In the 1830s the French chemist Joseph Louis Gay-Lussac developed a wet method: dissolve the sample in acid and titrate the silver out as silver chloride. It was faster and more precise than cupellation, and titration-based methods are still the referee standard for silver. Today assay offices also screen pieces with X-ray fluorescence, which reads a surface's composition in seconds without damage.

The law modernised too. The Hallmarking Act 1973 consolidated centuries of statutes into a single UK framework. In 1999 the system was simplified: a hallmark now needs only the sponsor's (maker's) mark, the fineness in parts per thousand (925 for sterling, 958 for Britannia), and the assay office mark. The lion passant and date letter became optional, though most makers still use them.

Internationally, the 1972 Vienna Convention created the Common Control Mark. A piece marked under it in one member country is accepted in the others without re-testing. Not every country hallmarks at all: the United States, for instance, has no compulsory independent assay, and a "sterling" stamp there is the maker's own claim.

The marks in a modern hallmark

A modern UK hallmark has three compulsory marks: the sponsor's mark, the fineness mark and the assay office mark. Three more are optional: a traditional fineness symbol, the date letter and, for export, the Common Control Mark.

Reading the marks today

A British hallmark is a compressed history. The sponsor's mark says who answers for the piece, the fineness number says what it is made of, and the town mark says who tested it. On older silver, the date letter and duty mark can place a piece to a specific year.

The principle has not changed since 1300: an independent body tests the metal and stamps its verdict where it cannot be removed. For anyone buying or selling silver, that small row of marks is still the most reliable guarantee there is.