A hallmark is an official mark or series of marks struck on items made of precious metals to guarantee the metal content, to advise of the year of manufacture, and to distinguish the manufacturer.
Hallmarking and assaying was introduced in some parts of Europe in the early ages as one of the first forms of customer protection. The word ‘hallmark’ originates from the 15th Century when craftsmen were required to bring their work to the Goldsmiths Hall of London to be tested (assayed) and stamped (hallmarked). This requirement remains unchanged nowadays.
Pure precious metals are too soft to be made into jewellery or other artefacts; silver, gold, platinum and palladium are all alloyed with other metals and rarely used in their pure states. Notably, the hallmark guarantees that the metal we purchase is of the legal standard in this country.
Because it is impossible to tell the purity of a metal by looking at it, thus making fraud easy, the assay office will scrape a tiny amount off metal from each item to test the level of each metal in that item. If the item meets the standards, it will be hallmarked (stamped).
(See article on Metals for further information.)