A hallmark is an official mark or series of marks struck on items made of metal, mostly to certify the content of noble metals—such as platinum, gold, silver and in some nations, palladium. In a more general sense, the term hallmark is used to refer to any standard of quality. Not to be confused with responsibility marks that are the marks of the maker.
General overview
Historically, hallmarks were applied by a trusted party: the "guardians of the craft" or, more recently, by an assay office (Assay mark). Hallmarks are a guarantee of certain purity or fineness of the metal, as determined by official metal (assay) testing.[1] Hallmarks include information not only about the precious metal and fineness, but the country from which the item was tested and marked. Some hallmarks can reveal even more information, e.g. the assay office, size of the object marked, year the item was hallmarked - referred to as a Date mark (also known as date letter).[2]
Distinguishment
Hallmarks are often confused with "trademarks" or "maker's marks". A hallmark is not the mark of a manufacturer to distinguish their products from other manufacturers' products: that is the function of trademarks or makers' marks. To be a true hallmark, it must be the guarantee of an independent body or authority that the contents are as marked. Thus, a stamp of "925" by itself is not, strictly speaking, a hallmark, but is rather an unattested fineness mark, generally stamped by the maker.
Prerequisites to hallmarking
History
Ancient Byzantine hallmarks
The control or inspection of precious metals was an ancient concept of examination and marking, by means of inspection stamps (punch marks). The use of hallmarks, at first on silver, has a long history dating back to the 4th century AD—there is evidence of silver bars marked under authority of the Flavius Julius Constans[3] around AD 350—and represents the oldest known form of consumer protection. A series or system of five marks has been found on Byzantine silver dating from this period, though their interpretation is still not completely resolved.[4]
Late Middle Ages
From the Late Middle Ages, hallmarking was administered by local governments through authorized assayers. These assayers examined precious metal objects, under the auspices of the state, before the object could be offered for public sale. By the age of the craft guilds, the authorized examiner's mark was the "master's mark", which consisted frequently of his initials and/or the coat of arms of the goldsmith or silversmith. At one time, there was no distinction between silversmiths and goldsmiths, who were all referred to as orfèvres, the French word for goldsmith.
Modern hallmarks
In the modern world, in an attempt at standardizing the legislation on the inspection of precious metals and to facilitate international trade, in November 1972 a core group of European nations signed the Vienna Convention on the Control of the Fineness and the Hallmarking of Precious Metal Objects.[14] Articles which are assayed and found by the qualifying office of a signatory country to conform to the standard, receive a mark, known as the Common Control Mark (CCM), attesting to the material's fineness. The multi-tiered motif of the CCM is the balance scales, superimposed, for gold, on two intersecting circles; for platinum, a diamond shape and for silver a mark in the shape of the Latin letter "M".
This mark is recognized in all the other contracting states, including: Austria, Cyprus, the Czech Republic, Denmark, Finland, Great Britain, Hungary, Ireland, Israel, Latvia, Lithuania, the Netherlands, Norway, Poland, Portugal, Sweden, Switzerland and Ukraine (see links below). Other nations monitor the activities of the convention and may apply for membership.
Complete international hallmarking has been plagued by difficulties, because even amongst countries which have implemented hallmarking, standards and enforcement vary considerably, making it difficult for one country to accept another's hallmarking as equivalent to its own. While some countries permit a variance from the marked fineness of up to 10 parts per thousand, others do not permit any variance (known as negative tolerance) at all.[15] Many nations abide by the Vienna system and procedures are in place to allow additional nations to join the Vienna Convention. Similarly, with the consent of all the current member states, the terms of the convention may be amended.
Marking techniques
Punching
Traditionally, the hallmarks are "struck" using steel punches. Punches are made in different sizes, suitable for tiny pieces of jewelry to large silver platters. Punches are made in straight shank or ring shank, the latter used to mark rings. The problem with traditional punching is that the process of punching displaces metal, causing some distortion of the article being marked. This means that re-finishing of the article is required after hallmarking. For this reason, and that off-cuts from sprues are often used for assay, many articles are sent unfinished to the assay office for assay and hallmarking.
Laser marking
A new method of marking using lasers is now available, which is especially valuable for delicate items and hollowware, which would be damaged or distorted by the punching process. Laser marking also means that finished articles do not need to be re-finished. Laser marking works by using high-power lasers to evaporate material from the metal surface. Two methods exist: 2D and 3D laser marking. 2D laser marking burns the outline of the hallmarks into the object, while 3D laser marking better simulates the marks made by punching.
Methods of assay
Precious metal items of art or jewelry are frequently hallmarked (depending upon the requirements of the laws of either the place of manufacture or the place of import). Where required to be hallmarked, semi-finished precious metal items of art or jewelry pass through the official testing channels where they are analyzed or assayed for precious metal content. While different nations permit a variety of legally acceptable finenesses, the assayer is actually testing to determine that the fineness of the product conforms with the statement or claim of fineness that the maker has claimed (usually by stamping a number such as 750 for 18k gold) on the item. In the past the assay was conducted by using the touchstone method but currently (most often) it is done using X-ray Fluorescence (XRF). XRF is used because this method is more exacting than the touchstone test. The most exact method of assay is known as fire assay or cupellation. This method is better suited for the assay of bullion and gold stocks rather than works or art or jewelry because it is a completely destructive method.
Touchstone
The age-old touchstone method is particularly suited to the testing of very valuable pieces, for which sampling by destructive means, such as scraping, cutting or drilling is unacceptable. A rubbing of the item is made on a special stone, treated with acids and the resulting color compared to references. Differences in precious metal content as small as 10 to 20 parts per thousand can often be established with confidence by the test. It is not indicated for use with white gold, for example, since the color variation among white gold alloys is almost imperceptible.
X-ray fluorescence
See also
- Assay office
- Merchant's mark
- Certification mark
- Mint mark
- Trademark
- Silver hallmarks
- State quality mark of the USSR
External links
References
- A Short History and Guide to English Silver Hallmarks Wallingford Arcade, retrieved 3 January 2025^
- C.J. Jackson. English Goldsmiths and Their Marks: A History of the Goldsmiths and Plate Workers of England, Scotland, and Ireland; with Over Thirteen Thousand Marks Reproduced in Facsimile from Authentic Examples of Plate and Tables of Date-letters and Other Hall-marks Used in the Essay Offices of the United Kingdom Macmillan, 1921, retrieved 2023-10-15^
- Constan Silver Coin