417, 333, 583, 585 and 875 on gold: what each stamp means

What the five numbers actually are

Every one of these is a millesimal fineness figure, meaning parts of pure gold per thousand parts of the finished alloy. 750 is 750 parts gold and 250 parts of something else. The same arithmetic runs through all of them. What changes from mark to mark is which country wrote the rule, and how that country decided to round the carat fraction.

375 and 916 are in the table as reference points rather than because anyone puzzles over them. If you want either of those on its own, what 375 means on gold and what 916 means on gold take them apart in full, and what 585 means on gold covers modern 14 carat. If the stamp reads 575 or 373 instead, neither is a UK standard, and the gold hallmark chart explains what those stamps usually are.

Why four of these five cannot be hallmarked in Britain

Schedule 2 of the Hallmarking Act 1973 sets out the standards of fineness a UK assay office is permitted to mark gold to. The list is 375, 585, 750, 916.6, 990 and 999. There is no entry for 333, 417, 583 or 875, so no British office in London, Birmingham, Sheffield or Edinburgh can strike those numbers, whatever the metal turns out to be on testing.

The international route does not add them either. The Convention on the Control and Marking of Articles of Precious Metals, whose Common Control Mark is recognised in the UK, covers gold from 999 down to 375. It stops at the same floor.

There is one practical consequence worth understanding. A foreign fineness number will not have a UK assay office symbol beside it, so what you are reading is a manufacturer’s declaration rather than an independent certification. That is a real difference, and it is the gap that testing closes. Our complete guide to UK gold hallmarks sets out what a full British mark looks like by comparison.

417: American 10 carat

417 is the United States 10 carat mark. Ten parts of gold in twenty-four is 41.666 per cent, and the stamp rounds it up to 417. The US National Stamping Act allows a tolerance of three parts per thousand on an article with no solder, and seven parts per thousand where solder is present, which is why an XRF reading of 414 or 415 on a 417-stamped chain is normal rather than alarming.

Ten carat is a little under 60 per cent base metal, mostly copper with silver and zinc. It is hard, it takes and holds a deep engraving, and over decades it can pick up a faintly pink cast or a dull surface film. That is the copper doing what copper does, not a sign that the piece is fake.

In a British drawer, 417 almost always means American family or an American posting. The best-known example is the US class ring, the heavy engraved school or college ring that American teenagers have bought for generations and that is overwhelmingly made in 10 carat. After that come imported rope and figaro chains, Black Hills gold rings with their applied leaves, and charm bracelets brought back from trips.

333: eight carat, and the one word you cannot use here

333 is 8 carat, 33.3 per cent gold and two-thirds something else. It has long been the customary minimum for jewellery sold as gold in Germany and Austria, and it appears in Dutch and Scandinavian retail as well. To a German shopper it is an ordinary, unremarkable everyday standard.

In Britain the law reads differently. 333 sits below 375, the lowest fineness the Hallmarking Act 1973 recognises for gold, so no UK assay office can hallmark it. The Act also makes it an offence for a person acting in the course of a trade or business to describe an un-hallmarked article as being wholly or partly made of gold. In practice that means a UK trader should not simply call an 8 carat piece "gold" without qualifying it. You can own it, wear it, inherit it and sell it. It is a labelling rule, not a judgement on the metal, and it does not stop the metal being bought and refined.

Because it is two-thirds base metal, 8 carat is noticeably paler and cooler than 9 carat, and some 333 alloys darken or develop a greenish tinge against skin over the years. Neither tells you anything about whether it is genuine. XRF reads the actual composition in seconds, which is the point of testing rather than trusting a stamp. XRF testing explained covers how that works.

583 and 585: two thousandths apart

583 was the Soviet 14 carat standard, one of five gold standards in the Soviet system alongside 375, 500, 750 and 958. Russian production moved to 585 in the 1990s to line up with international practice. The year is commonly given as 1994, though we have not found a primary source we would stake a claim on, so treat the date as approximate. What is not in doubt is what the number tells you: a 583 stamp means the piece is Soviet-era.

The gap between the two standards is two parts per thousand. On a 10 gram wedding band that is 0.02 grams of pure gold, a difference far too small to matter in practice. Anyone presenting 583 as materially inferior to 585 has not done the arithmetic.

Soviet pieces often carry a state assay mark showing a hammer and sickle inside a five-pointed star, raised in relief between 1958 and 1965 and recessed from then on, usually with one or two Cyrillic letters identifying the assay office. Those marks are worth photographing before anything is sold, because a piece with an intact Soviet mark set is sometimes of more interest to a collector than to a refiner.

875: 21 carat, or silver

875 is 21 carat, 87.5 per cent gold, and it is the working standard of Gulf gold jewellery. Saudi Arabia, the United Arab Emirates, Kuwait, Qatar, Jordan and Egypt all trade heavily in 21 carat, because it holds the deep yellow colour that market expects while staying just workable enough for chains, bangles and the heavy link sets sold by weight in the souks. It reaches Britain through Gulf work postings, family in the region, and holiday purchases in Dubai.

The two separate in seconds without any equipment. 21 carat gold is unmistakably deep yellow and startlingly heavy for its size, because gold is close to twice as dense as silver. A silver piece of the same dimensions feels ordinary in the hand and is white or grey, going grey-black where it has tarnished. If you are unsure, photograph the mark and the piece together and send it on WhatsApp before posting anything.

What each mark is worth as metal

Nothing about a foreign mark changes the valuation method. The metal content of any piece is its weight multiplied by its fineness, and the live market decides the rest. The share of pure gold in one gram of each alloy follows directly from the fineness.

That column is the pure gold inside one gram of alloy. To turn it into money you multiply by the live gold price, then allow for refining, assay, handling, the working-capital gap and margin, which sit between the market and every consumer offer at every reputable firm. The components are broken down in spot price versus scrap price.

The number that surprises people is what happens when weight is taken into account. A 30 gram German 333 chain holds 9.99 grams of pure gold. A 6 gram Gulf 875 ring holds 5.25 grams. The chain has almost twice the recoverable gold of the ring despite carrying the lowest mark in the table. Mass matters at least as much as fineness, which is why guessing from the stamp alone is a poor way to work out what a mixed drawer is worth.

Final offers depend on inspection, item weight, purity, hallmarks, stones, non-gold components, condition and the live precious-metal market.

When posting is not the right answer

We buy metal, and we pay on measured metal content. For some pieces carrying these marks, that is not the best route, and it is worth saying so plainly before you pack anything.

• Recent, unworn 21ct Gulf jewellery. In the Gulf, 21 carat is bought and sold back close to metal value with a modest making charge on top, so a set bought in Dubai last year and never worn may do better sold back into that market through family, or to a UK dealer who specialises in 21 carat as jewellery, than melted for its content here.
• American class rings. There is a small but real collectors' market for US class rings with a named school, year and initials. A quick search on the school name is worth five minutes before treating one as scrap.
• Intact Soviet pieces with a full mark set. A 583 ring or an 875 silver case with a clean hammer-and-sickle assay mark and a maker’s mark can hold collector interest above its melt figure. Photograph the marks and check before deciding.
• A single very light 333 item. A 1.5 gram 8 carat charm holds half a gram of gold. On its own that is not worth the trip to the Post Office. Put it in with other items, or leave it where it is.
• Anything marked 417 GF, 333 GP, 14K GE or similar. Those suffixes mean gold filled, gold plated or gold electroplated, not solid gold. Gold filled versus gold plated versus vermeil explains what each is actually worth.

Everything else in this family posts the same way as British-marked gold. Send a photo first, get an indicative figure, and decide afterwards. The full method is on the sell gold by post page, and how we value gold sets out the calculation itself.

How a foreign-marked parcel is handled

1. Photograph the marks and the piece and send them on WhatsApp to 07944 014111. We will tell you honestly what the mark appears to be, including when it looks like silver rather than gold, and what we can and cannot tell from a photograph.
2. If you want to go ahead, we send a prepaid Royal Mail Special Delivery label, usually within 30 minutes during working hours. Royal Mail cover may be available up to £2,500 depending on the postal method and cover level used.
3. Every parcel is signed for on arrival and opened at our Bristol office, where each item is weighed and XRF-tested. The foreign stamp is the starting point; the tested composition is what the offer is built from.
4. You get a written, itemised offer showing the purity found, the weight and the figure. Nothing is firm before inspection.
5. Accept and we aim to pay by Faster Payments within one working hour of acceptance. Decline and the whole parcel comes back to you free of charge by tracked post.

Mismatches between stamp and metal do happen with imported pieces, in both directions. A 417 chain repaired with a lower-carat solder tests slightly under. A 333 piece from a maker working above the minimum tests slightly over. Either way the offer follows the measured metal rather than the stamp, which is the only version of this that is fair to both sides. If you only want to know what a foreign-marked piece is made of, it can be tested by XRF for its actual gold content without selling it.

Sources

• Hallmarking Act 1973, Schedule 2, standards of fineness for gold, silver, platinum and palladium: legislation.gov.uk
• Assay Office London, hallmarking guidance notes, legal standards and exemption weights: assayofficelondon.co.uk
• Convention on the Control and Marking of Articles of Precious Metals, finenesses covered by the Common Control Mark: Dublin Assay Office and hallmarkingconvention.org
• US National Stamping Act tolerances, as applied by the FTC Jewelry Guides at 16 CFR Part 23: ecfr.gov

Where a fact is contested we have said so rather than smoothing it over. The date Russia moved from 583 to 585 is the clearest example: it is widely reported as 1994, and we have not found a primary source for it, so it is given here as approximate.