What the marks inside the shank actually promise

Turn a ring over and look inside the shank. On anything made or sold in France, the United Kingdom, Ireland or a dozen other jurisdictions you will find a row of very small punched marks. People read them as a general certificate of quality. They are not that. They are a certificate of one thing, tested destructively, by somebody with no financial interest in the answer.

What is actually being certified

A hallmark certifies the fineness of the precious metal: how many parts per thousand of the alloy are gold, or silver, or platinum. That is it. 750 means 750 parts gold in 1000 — eighteen carat. 950 on platinum means 950 parts platinum. The mark says nothing whatsoever about the stones, the quality of the setting, the design, or whether the piece is worth what you paid for it.

It is worth being blunt about that, because a hallmark is often produced in a shop as though it settled a broader question. It settles a narrow one completely and an important one not at all.

Who does the testing

The testing is done by an assay office, which is independent of the maker. In the United Kingdom there are four — London, Birmingham, Sheffield and Edinburgh — and each has its own town mark: a leopard’s head, an anchor, a rose, a castle. In France the guarantee marks are older still and are punched by the state: the eagle’s head for 18 carat gold, the Minerva head for silver, the dog’s head for platinum on older work.

The office does not take the maker’s word for the alloy. A scraping is taken from the piece and assayed, historically by cupellation — the sample is melted with lead in a porous bone-ash cup, the base metals oxidise into the cup, and what is left is weighed. Modern offices use X-ray fluorescence for screening and still fall back on fire assay when a piece is borderline, because XRF reads the surface and the surface is exactly where a dishonest maker would put the gold.

The four marks and the fifth

A full British hallmark carries three compulsory marks: the sponsor’s mark, which identifies who submitted the piece; the fineness in numerals; and the assay office town mark. A fourth, the date letter, is optional now but is the one collectors care about, because it dates the piece to a single year. A fifth mark, the traditional fineness symbol — a crown for gold, a lion passant for sterling — may also be struck on request.

The sponsor’s mark is worth dwelling on. It is not a maker’s mark. It identifies the party who submitted the article for hallmarking, which may be the workshop, or may be a retailer who had the work made elsewhere. A piece bearing a famous house’s sponsor mark was submitted by that house. Whether it was made at their bench is a separate question that the hallmark does not answer.

Where the law starts

Hallmarking is compulsory above a weight threshold, and the thresholds are lower than most people expect: in the UK, 1 gram for gold, 0.5 grams for platinum, 7.78 grams for silver. Below that a piece may be sold undescribed. This is why a very light chain often carries no marks at all, and why the absence of a hallmark on a small item is not in itself evidence of anything.

What we add to it

Every piece that leaves this atelier carries the compulsory marks, the date letter, and two things the law does not require: the house reference, which ties the piece to its drawing and its stone paperwork in our own records, and the mark of the setter who finished it. The second one exists because a piece that can be traced to one pair of hands tends to be finished as though it can.