hall·mark | ˈhȯl-ˌmärk
A mark stamped on jewelry throughout much of the world to attest to the purity of the metal after assay
European hallmarks are legally required and date back to the early Middle Ages--an early form of consumer protection against fraud. Marks are not officially required in the United States, but are carried by custom and practice. Marks may indicate the purity of the metal, the maker, the country of manufacture, and/or the date that the piece was assayed or had its design registered.