When did they stamp sterling jewelry taxed?

Sterling silver jewelry became subject to taxation in the United States with the introduction of the Tax Reform Act of 1969, which established a sales tax on certain luxury items. However, the specific practice of stamping jewelry as a mark of quality and authenticity predates this tax and has roots in various regulations dating back to the 14th century in England. The hallmarking system was designed to assure consumers of the metal's purity, with "sterling" indicating a minimum silver content of 92.5%.