An assay mark is the oldest form of consumer protection and was introduced to England in 1327 when the medieval guilds began testing silver to ensure that it was of the required sterling standard. Sterling was used as an international medium of exchange and was evidenced by an image of the monarch’s head on coinage and hallmarks impressed on silverware. Even after the demise of the silver content itself in coinage the standard has in Britain been strictly applied to silverware.
Every piece of precious metal has to be submitted to an Assay Office for independent testing and hallmarked. “Hall” is a craft guild headquarters, eg Goldsmiths’ Hall in London, which is chartered to regulate the trade. It is illegal to sell silver in Britain without hallmarks. The concept of sterling originated when silversmiths found fine (i.e. pure) silver too soft to fashion alone and so had to alloy it with base metal in order to harden it. The most compatible base metal is copper and when a small amount, 75 parts to 1000 parts of total weight, is mixed with the pure silver, the resulting sterling (925) alloy produces the following ideal qualities:-
The sterling alloy is variously known as sterling, solid silver or just silver, since a lower standard has, for most of the second Millennium, been illegal in Britain.
To protect the intrinsic value of silver from fraud or error when it is allowed with base metal all silver is submitted to quasi-government Assay Offices whose laboratories examine physical scrapings from each piece. This is called the assay and was originally done by an avid colour variation test on a touchstone. Nowadays analysis is by sophisticated chemical means to ensure the requisite standard. Passing the assay in indicated by hallmarks. No other country has had this consumer protection for so long (nearly 700 years).
A European Convention imposed changes from 1 January 1999. A Millesimal Fineness mark is now obligatory. It duplicates the Lion Passant introduced in England as long ago as 1540. We are permitted to continue using this historic English mark. The obligatory hallmarks are now the Maker’s, Town and Millesimal marks. This new European Convention also permits the lower 800 standard mostly used in Continental Europe.”