18k gold watch cases: fineness, responsibility mark and official hallmarking in Switzerland
In Switzerland, an 18k gold watch case carries the fineness mark 750 and a registered responsibility mark, and it must undergo official control before it is placed on the market, whether it was made in Switzerland or imported. The Assay Office checks the fineness of every part, then strikes the official hallmark, a St Bernard dog’s head. A brand that has its cases made by others can register its own trademark as its responsibility mark.
These rules come from the Federal Act on the Control of the Trade in Precious Metals and Precious Metal Articles (Precious Metals Control Act, PMCA, SR 941.31)1 and its ordinance (PMCO, SR 941.311)2. Control is carried out by the Precious Metals Control, which reports to the Federal Office for Customs and Border Security (FOCBS)4. The article numbers below refer to these two texts; the official versions are in German, French and Italian, and Fedlex publishes an English translation with no legal force. We take the rules in the order a brand meets them, from the choice of alloy to the polishing of a case that has already been hallmarked.
750 parts per thousand in every part
Fineness is the proportion of pure precious metal in an alloy, expressed in parts per thousand (Art. 3 PMCA). For gold, the Act recognises five legal standards: 999, 916, 750, 585 and 375 (Annex 2)1. 18k gold is gold at 750: the carat counts fine gold in twenty-fourths, and 18/24 equals 750/1000. The ordinance allows the carat figure as an additional mark next to the fineness in parts per thousand, provided it matches the actual composition (Art. 46 para. 4 PMCO)2.
The rule that bears directly on the engineering of a case is Article 7 paragraph 2 of the Act: all parts of a precious metal article must at least meet the fineness specified for the article. The Central Office may make exceptions on technical grounds. The ordinance turns this into specific rules:
- solders must in principle be of the same metal and the same fineness as the article; where the Central Office permits a lower-fineness solder, a tolerance of no more than ten parts per thousand applies to the fully melted object (Art. 36);
- the article must not contain any metal or substance other than the precious metal of its main mass (Art. 37);
- mechanisms and components made of other materials may be allowed on technical grounds, on terms set by the Central Office (Art. 42);
- if a case combines several gold alloys, the fineness mark follows the lowest one (Art. 46 para. 3).
The ordinance provides a fineness tolerance only for these permitted solders. A case marked 750 must therefore reach at least 750 in each of its parts, unless the Central Office has allowed an exception. The alloy and its suppliers are chosen with this in mind; our article on choosing a watch case material compares gold with the other options.
The responsibility mark of a brand that has its cases made
Every precious metal, multi-metal or plated article must carry a responsibility mark in addition to its fineness mark (Art. 9 para. 1 PMCA). The FOCBS compares it to a signature4: by applying the mark, or having it applied, the owner becomes responsible for the correctness of the marks on the article (Art. 58 para. 1 PMCO).
A brand does not need a workshop to have one. The Act allows a business that does not produce the articles it uses to have its trademark stamped on them as a responsibility mark (Art. 9 para. 2 PMCA). For watch cases, several businesses can also share a collective responsibility mark, each with its own control number, under rules approved by the Central Office (Art. 9 para. 3 PMCA; Art. 60 and 61 PMCO).
Registration
The mark is registered with the Central Office for Precious Metals Control. The FOCBS asks for a signed application form and three different black and white designs, and charges CHF 800 for twenty years4. The registration can then be extended by twenty years at a time, on an application filed before it expires (Art. 12 para. 1bis PMCA). The register is public, and each registration is published in the Swiss Official Gazette of Commerce (Art. 73 and 75 PMCO).
The design must be distinguishable from registered marks at a magnification of 2.5 (Art. 59 PMCO) and must not be open to confusion with an official hallmark (Art. 10 PMCA). Because it will be struck or laser-engraved at a very small size, the FOCBS recommends a simple design, such as a combination of letters or figures. A brand based outside Switzerland, or one not entered in the commercial register, may be required to provide security (Art. 11 para. 2 PMCA).
Who marks what in a chain of subcontractors
The responsibility mark is applied at the same time as the fineness mark (Art. 9 para. 4 PMCA), and the fineness mark sits close to it4. It is written in Arabic numerals and must be visible, legible, indelible and at least 0.5 mm high (Art. 46 PMCO).
Loose components and semi-finished products may already carry a fineness mark and a responsibility mark. The person who assembles or completes the article is then responsible for ensuring that its marks match its composition (Art. 52 PMCO). When a case passes through several workshops, the contract should therefore state who applies which mark, on which part and at what stage.
Official control, before the case is placed on the market
Precious metal watch cases may not be placed on the market before they have undergone official control. The control must be applied for by whoever makes the cases or places them on the market (Art. 13 para. 1 PMCA)1. For other precious metal articles and for multi-metal articles, the control is optional (Art. 13 para. 2).
The ordinance sets out how far this obligation reaches2. A watch case, within the meaning of the Act, is anything that houses a watch movement (Art. 38). It is deemed to be placed on the market as soon as it leaves the plant where it was made, and the application goes to the Assay Office for that area (Art. 82 paras 2 and 3). The Central Office regulates the hallmarking of unmachined parts and the later submission of additional parts or finished articles (Art. 121 para. 4). Where machining, finishing and assembly are carried out by different workshops, the stage at which the case is submitted, and who applies, should be settled with the Assay Office before the first series.
Submitting the cases
Only articles bearing a legal fineness mark and a responsibility mark are accepted for control (Art. 16 PMCA). Cases are submitted clean, open and complete; if only parts are hallmarked, the applicant signs to accept liability for the conformity of the finished article (Art. 85 PMCO). They must also be far enough along that finishing will no longer alter either the marks or the part.
With the articles, the FOCBS asks for the hallmarking application, a hallmarking plan showing where the official hallmark should go, and samples from the same alloy, the same melt and the same series; their analysis is destructive4. Applications can be created and tracked in Prezius, the online application of the Precious Metals Control3.
The assay
The fineness check covers every part of the article (Art. 91 PMCO). Material is taken by scraping or cutting, and the assay is carried out on clean metal, free of surface treatment and solder (Art. 93). Residues from the assay are returned with the articles (Art. 95). If the fineness does not match, the Assay Office refuses to hallmark and the Central Office orders a second assay (Art. 17 PMCA); where the objection is upheld, the articles are as a rule made unusable and then returned (Art. 105 PMCO).
The official hallmark and where it goes on the case
The Assay Office then strikes the official hallmark, the same for all precious metals and all standards of fineness: a St Bernard dog’s head3. It bears the letter of the Assay Office; the FOCBS has an office in Geneva, whose letter is G (PMCO, Annex II)5.
| Hallmark | Height | Width |
|---|---|---|
| Large hallmark | 1.6 mm | 2 mm |
| Small hallmark | 0.8 mm | 1 mm |
| Small hallmark applied by laser ablation | 0.5 mm | 0.625 mm |
The official hallmark is placed close to the fineness mark and the responsibility mark, and at least one official hallmark must be visible on the outside of the article. If all the marks on a watch case are on the inside, at least one fineness mark must be visible from the outside (Art. 117 PMCO). These areas are chosen when the case is engineered, on a surface that finishing will not rework. A written agreement can also allow the business that makes the cases to apply the official hallmark itself, on its own premises, under the Assay Office’s supervision (Art. 117a).
What the official hallmark attests
The official hallmark attests that the fineness mark and the responsibility mark are accurate (Art. 15 PMCA). An imported case that is controlled in Switzerland receives the same official hallmark as a Swiss case. Whether a case counts as Swiss is governed by other texts, which we explain on our page Swiss made, Geneva provenance and the Geneva Seal (Poinçon de Genève). The Geneva Seal is covered in its own section on the same page.
Import and export
A finished watch imported in a precious metal case is subject to the same compulsory control (Art. 20 para. 1 PMCA). The customs office that clears it sends it on to the competent Assay Office (Art. 20 para. 4)1. As for a Swiss case, only articles that already carry the fineness mark and the responsibility mark are accepted for control (Art. 16 PMCA).
For export, precious metal watch cases must bear the official hallmark (Art. 21 para. 1 PMCA). The Swiss business that makes them may add, on its own responsibility, the marks required or customary in the destination country (Art. 21 para. 2). Official hallmarking may be waived for cases sent directly to a state where the control of watch cases is compulsory; the Central Office determines these cases from the foreign legislation and publishes them as guidelines (Art. 82 para. 4 PMCO).
Switzerland is a party to the 1972 Vienna Convention on the control and marking of articles of precious metals. It also has bilateral agreements with France, Italy, Austria, Spain, Russia and Kazakhstan (Art. 126 para. 3 PMCO)6. An article bearing the Swiss official hallmark together with the Convention’s Common Control Mark, a pair of scales, is not hallmarked again in the other contracting states, and its responsibility mark does not need to be registered there. The Common Control Mark is optional; it requires the chemical symbol of the metal in front of the fineness, for example “Au 750”4.
Steel and gold, plated, coiffe or: what changes
The Act distinguishes precious metal articles, multi-metal articles, plated articles and imitations. A case moves from one regime to another depending on how much gold it contains and how the gold is applied.
| Category | Material requirement | Marks | Official control |
|---|---|---|---|
| Solid 750 gold | Every part at least 750 (Art. 7 PMCA) | “750” and responsibility mark; carat figure allowed in addition | Compulsory for a watch case (Art. 13 PMCA) |
| Steel and gold multi-metal | Gold at a legal fineness; the metals visible from the outside and distinguishable by colour (Art. 7a PMCA) | Fineness and responsibility mark on the gold; type of metal or “Metal” on the steel (Art. 48 PMCO) | Optional |
| Gold-plated | Gold layer of at least 5 µm, at a fineness of at least 585 (Annex 1 PMCA) | “Plaqué” with L or G, or for a watch case GR or GP followed by the thickness; responsibility mark; no fineness mark (Art. 49 and 50 PMCO) | Not provided for: the official hallmark covers precious metal and multi-metal articles (Art. 15 PMCA) |
| Coiffe or | Gold layer of at least 200 µm, at a fineness of at least 585, inseparably attached to the case and its additional parts, including straps (Art. 43 PMCO) | GC, thickness in microns, responsibility mark (Art. 49 para. 4 PMCO) | Not provided for (same reason) |
The steel and gold case
A steel and gold case is a multi-metal article: gold at a legal fineness combined with a base metal (Art. 1 para. 5 PMCA). It can be sold as such if its marks state its actual composition, with the fineness in parts per thousand for the gold and the type of metal for the rest. The metals must be visible from the outside and distinguishable by colour, and the article must not look like a plated one (Art. 7a PMCA). Official hallmarking of a multi-metal case is optional3; if it is requested, the gold part must carry the fineness mark and the responsibility mark (Art. 83 PMCO).
Plated, coiffe or and imitations
The prescribed thickness of a plated layer must be present over the whole surface that determines the article’s appearance or function, except at points that a sphere 5 mm in diameter cannot touch. The tolerance on the thickness is 20 % (Art. 43 paras 2 and 4 PMCO). A plated article never carries a fineness mark (Art. 8 para. 4 PMCA). A gold-coated case that does not meet these requirements, or is not marked as plated, is an imitation: it may be described as gilded, with no fineness mark and no thickness figure (Art. 2 para. 3 and Art. 8 para. 3 PMCA; Art. 50 PMCO).
Soldering, laser build-up and polishing on a gold case
In our workshop in Plan-les-Ouates, jewellery work on the case (laser spot welding and build-up, torch and belt-furnace soldering, casting rework) and polishing are carried out on steel, titanium and precious metals. On a gold case, the rules above affect this work in several places.
Any metal added by soldering or laser build-up becomes part of the article, and Article 7 of the Act requires it to reach at least the fineness of the case. For solders, the ordinance requires in principle the same metal and the same fineness, unless the Central Office permits otherwise (Art. 36 PMCO). The filler alloy should therefore be agreed in writing with the workshop before the first part.
Polishing and satin-finishing can remove or damage a mark. A new hallmark must then be obtained from the Assay Office that applied the original one; if the earlier hallmarking can be proven, the case is not tested again and no fee is charged (Art. 122 PMCO). This is a reason to know where the marks are before reworking a surface, and to submit the case for control once finishing will no longer touch them.
In after-sales service, replacing part of a hallmarked case means a new assay and a new hallmark. The replaced pieces are presented to the Assay Office, which removes their hallmarks. The Assay Office charges half the hallmarking fee, and nothing if it is proven that the part was replaced because of a manufacturing error (Art. 121 PMCO). How we handle a repair is described on our page on watch after-sales service for brands.
Gold waste from the workshop
Filings, turnings, cuttings, polishing waste and spoiled parts: the Act classes waste from the processing of precious metals as melt material (Art. 1 para. 3 let. b PMCA; Art. 35a PMCO). Only the holder of a melter’s licence may make melt products commercially (Art. 24 PMCA). The Central Office also grants an individual melting authorisation, valid for twenty years, which allows a business to melt the waste from its own activity but never that of others4. Anyone who buys this material commercially must ascertain and document its origin, and must register with the Central Office if entered in the commercial register (Art. 31a PMCA).
For a brand, the question is mainly contractual: who keeps the gold waste from a series, how it is weighed and who is credited with its value. It should be settled before the metal is handed to the workshops.
Frequently asked questions
Does a gold watch sold in Switzerland need the official hallmark?
Its case does. A watch case made of precious metal, whether made in Switzerland or imported, must undergo official control before it is placed on the market (Art. 13 and 20 PMCA), subject to international agreements. For other gold articles, the control is optional.
Can a brand without its own workshop have its own responsibility mark?
Yes. The Act allows a business that does not produce its articles itself to have its trademark stamped on them as a responsibility mark (Art. 9 para. 2 PMCA). The brand registers the mark with the Central Office for Precious Metals Control and is then responsible for the correctness of the marks.
Does a steel and gold case have to be officially hallmarked?
No, official hallmarking is optional for a multi-metal case. It must still carry the fineness mark and the responsibility mark on the gold part, and the type of base metal on the other part (Art. 7a PMCA; Art. 48 PMCO).
Does a repolished case have to be hallmarked again?
Yes, if polishing has removed or damaged the marks. The application goes to the Assay Office that applied the original hallmark; if the earlier hallmarking can be proven, the case is not tested again and no fee is charged (Art. 122 PMCO).
Is the Swiss official hallmark recognised abroad?
In the states of the Vienna Convention, yes, when it is accompanied by the Common Control Mark. With France, Italy, Austria, Spain, Russia and Kazakhstan, bilateral agreements govern hallmarking, each for the articles it covers (Art. 126 para. 3 PMCO). For other countries, the FOCBS advises checking with the authorities of the destination country, and the Act allows the marks required there to be added (Art. 21 para. 2 PMCA).
Sources
- SR 941.31, Federal Act on the Control of the Trade in Precious Metals and Precious Metal Articles (Precious Metals Control Act, PMCA), status as of 1 July 2023: Art. 1 to 3, 7 to 17, 20, 21, 24 and 31a, Annexes 1 and 2. English translation on Fedlex (no legal force) accessed 29 September 2026
- SR 941.311, Precious Metals Control Ordinance (PMCO), status as of 1 January 2024: Art. 35a to 52, 58 to 75, 81 to 126, Annex II. English translation on Fedlex (no legal force) accessed 29 September 2026
- FOCBS, Precious Metals Control, “Official controlling and hallmarking”. FOCBS page accessed 29 September 2026
- FOCBS, questions and answers on precious metals control: marks, responsibility mark, official hallmarking and Common Control Mark, melter’s licence, import and export. FOCBS page (in French) accessed 29 September 2026
- FOCBS, “Locations of precious metals control in Switzerland”. FOCBS page accessed 29 September 2026
- FOCBS, “International conventions”: Vienna Convention of 15 November 1972 and bilateral conventions. FOCBS page accessed 29 September 2026
This article summarises official texts and cites its sources. It is not legal advice; for a specific case, the Central Office for Precious Metals Control answers questions from businesses.