Hallmark
A hallmark is a mark or series of marks struck on items made of precious metals - platinum, gold, silver and in some nations, palladium.

# General overview

## Hallmarks defined
A hallmark, is a mark or series of marks struck on items made of precious metals - platinum, gold, silver and in some nations, palladium.  In a more general sense, the term hallmark can also be used refer to any distinguishing characteristic or trait.
Historically, hallmarks were applied by a trusted party: the 'guardians of the craft' or nowadays by an assay office. These marks guarantee a certain purity or fineness of the metal.

## Hallmarks distinguished from marks
These official hallmarks should not be confused with a markings, which often are just a number such as 750 or 925 (albeit intended to denote the fineness of the metal), which is done by the manufacturer, and unfortunately may not always reflect the true purity of the metal.

## Pre-requisites to hallmarking
Notwithstanding the hallmarking systems of many nations require, as a prerequisite to official hallmarking, that the maker or sponsor itself mark upon the item a responsibility mark and a claim of fineness.  Responsibility marks are also required in the U.S. despite the fact that there is no official hallmarking scheme in that country.  Nevertheless, in nations with an official hallmarking scheme, the hallmark is only applied after the item has been assayed to determine that its purity conforms not only to the standards set down by the law but also and with the makers claims as to metallurgical content.

## Systems differs from nation to nation
In some nations, such as the UK, the hallmark is made up of several elements including: a mark denoting the type of metal, the maker/sponsor's mark and the year of the marking.  In other nations, such as Switzerland, the hallmark is a single mark regardless of metal or fineness, although that mark is augmented by a responsibility mark (known as a sponsor's mark in the UK) and the makers claim as to the fineness.  Among a group of nations which are signatories to an international convention known as the Vienna Convention, additional, optional, yet official marks may also be struck by the assay office. These have the effect of easing import obligations among and between the member states.

# History of hallmarking

## 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 fourth century AD 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.

## Hallmarking in the Late Middle Ages
However, from the Late Middle Ages, hallmarking was administered by local governments through authorized assayers. These assayers examined precious metal goods, under the auspices of the state, before the good could be offered for public sale.  By the age of the Craft Guilds, the authorized examiners mark was the masters 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 among silversmiths and goldsmiths who were all referred to as orfevres, the French word for goldsmith.  The Master Craftsman was responsible for the quality of the work that left his atelier or workshop, regardless of who made the item.  Hence the responsibility mark is still known today in French as le poincon de maitre literally "the maker's punch". In this period, fineness was more or less standardized in the major European nations (writ: France and England) at 20 karats for gold and 12 to 13 lots (75% to 81%) for silver, but the standards could only be partly enforced owing to the general nature of the time.

### France
Hallmarking is Europe's earliest form of consumer protection. Hallmarking in Europe appears  first in France, with the Goldsmiths Statute of 1260promulgated under Etienne Boileau, Provost of Paris, for King Louis IX "St. Louis". A standard for silver was thus, established. In 1275, Philippe III "the Bold" prescribed by royal decree, the mark for use on silver works, along with specific punches for each community's smiths. In 1313, his successor, Philippe IV "the Fair" expanded the use of hallmarks to gold works.

### England
In 1300, King Edward I of England enacted a statute ordering that all silver articles must meet the Sterling silver standard (92.5% pure silver), and should be assayed by 'guardians of the craft', who would then mark the item with a leopard's head.  In 1327, King Edward III of England granted a charter to the Worshipful Company of Goldsmiths (more commonly known as the Goldsmiths' Company), marking the beginning of the Company's formal existence. This entity was headquartered at London's "Goldsmiths' Hall of the Worshipful Company of Goldsmith" from whence the English term "hallmark" is derived.
In 1355, individual maker marks were introduced in France, which concept was later mirrored in England in 1363, adding accountability to the two systems.

### Switzerland
In 1424, the French Archbishop Jean de Brogny, after having consulted with a council of eight Masters Goldsmiths from Geneva, enacted a regulation on the purity and hallmarking of silver objects following the French standards for application in Geneva. Although gold was certainly used for articles, the regulation was silent on gold standards and its hallmarking. (Today in Switzerland, only precious metal watch cases must be hallmarked.  Perhaps this attests to the significance of watches to the Swiss economy.  The hallmarking of other items including silverware and jewelry is optional.)

### Augmentations in France and England
In 1427, the date letter system was established in France, allowing the accurate dating of any hallmarked piece.
In 1478, the Assay Office was established in Goldsmiths' Hall.  At this time, the date letter system was introduced in England.
In 1697, a higher standard of silver, known as the Britannia standard (95.8% silver) was made compulsory in England to protect the new coinage which was being melted down by silversmiths for the silver.  The Sterling standard was restored in 1720.

# 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 1973 a core group of European nations signed the Vienna Convention on the control of the fineness and the hallmarking of precious metal objects. Those articles, which are assayed and found to be in conformity by the qualifying office of a signatory country, 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.  Many nations monitor the Vienna system and procedures are in place to allow additional nations to join the Vienna Convention. Similarly, with the consent all the current member states, the terms of the Convention may be amended.
The most significant item currently up for debate is the recognition of palladium as a precious metal.  Some member nations recognize palladium as a precious metal while others do not.

## List of countries with statutory independent hallmarking as of 2007
Nations noted in bold are Vienna Convention members (as of 2007) and each recognizes the others hallmarks. (Click the external link for hallmark illustrations - text is French, scroll down for illustrations). For an overview in table form (in English) click here.

## In the UK
The Hallmarking Act 1973 made Britain a member of the Vienna Convention as well as introducing marking for platinum, a recognized metal under the Convention.  All four remaining assay offices finally adopted the same date letter sequences. The latest changes in 1999 were made to the UK hallmarking system to bring the system closer into line with the European Union (EU).
As it now stands, the compulsory part of the UK hallmark consists of the sponsor or maker's mark, the assay office mark, and the standard of fineness (in this case silver, 925 parts in 1000).
These are shown in the top of the two example hallmarks.  The bottom example shows the extra marks that can also be struck, the lion passant, indicating Sterling silver, the date mark (lowercase a for '2000'), and in this example, the 'Millennium mark', which was only available for the years 1999 and 2000.  The bottom example bears the Yorkshire rose mark for the Sheffield Assay Office.

## In Switzerland
Although hallmarking in the Swiss territories dates back to Geneva in the 1400's there was no uniform system of hallmarking in Switzerland until 1881.  Before that time, hallmarking was undertaken at the local level by the Swiss cantons.  With the introduction of the  Swiss system of hallmarking in 1881, there was uniformity throughout the nation. Under the current law, on all gold, silver, platinum or palladium watches cases made in Switzerland or imported into Switzerland, (Fr.) there shall be affixed, near the Maker's Responsibility Mark and his indication of purity, the official Hallmark, the head of a Saint-Bernard dog (illustrated below). Only precious metal watch cases must be hallmarked. Swiss hallmarking for other articles such as jewelry and cutlery is optional. In addition to the Swiss hallmark, all precious metal goods may be stamped with the Common Control Mark of the Vienna Convention.

## In the Netherlands
The Dutch, who are members of the International hallmarking Convention, have been striking hallmarks since at least 1814.  Like many other nations, the Dutch require the registration and use of Responsibility Marks, however, perhaps somewhat unique, the Dutch publish a book entitled "Netherlands' Responsibility Marks since 1797" (in three volumes and in the English language) illustrating all the responsibility marks registered there since that time. This is significant since producers that exported precious metal good to the Netherlands would have been required to register their marks.
The Dutch government markets their assay services/office as the "Jewellery Gateway in and to Europe." The Netherlands' hallmarks are also recognized in other E.U. countries and thus can be sold in Austria, France, Ireland, Portugal, Spain and the United Kingdom without further testing. The Netherlands' hallmarks are also recognized in Belgium, Denmark, Finland and Sweden, which have voluntary hallmarking systems.
The Dutch assay office is located in Gouda between the Amsterdam and Rotterdam Airports. The Dutch recognize platinum, gold, silver and palladium as precious metals.

# 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 former for normal punching with a hammer, and the later used with a press 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.

## The 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
The modern X-ray fluorescence is also a non-destructive technique that is suitable for normal assaying requirements. It typically has an accuracy of 2-5 parts per thousand and is well-suited to the relatively flat and large surfaces. It is a quick technique taking about three minutes, and the results can be automatically printed out by the computer. It also measures the content of the other alloying metals present. It is not indicated, however, for articles with chemical surface treatment or electroplating.

## The Fire Assay (Cupellation)
The most elaborate but totally destructive assay method is the fire-assay, also known as cupellation, with an accuracy of 1 part in 10,000. In this process the article is melted, the alloys separated and constituents weighed. Since this method is totally destructive, when this method is employed for the assay of jewelry, it is done under the guise random or selective sampling. For example if a single manufacturer deposits a lot of rings or watch cases, while most are assayed using the non-destructive methods a few pieces from the lot are randomly selected for fire assay.

## Other methods
There are methods of assay noted above which are more properly suited for finished goods while other methods are suitable for use on raw materials before artistic workmanship has begun. Raw precious metals (bullion or metal stock) are assayed by the following methods: silver is assayed by titration, gold is assayed by cupellation and platinum is assayed by ICP OES spectrometry.