A Path to Steam
U. S. Assay Office
Assay offices are institutions set up to assay (test the purity of) precious metals, in order to protect consumers. Upon successful completion of an assay, (i.e. if the metallurgical content is found to be equal or better than that claimed by the maker and it otherwise conforms to the prevailing law) the assay offices typically stamp a hallmark, punze, or poinçon on the item to certify its metallurgical content. Hallmarking first appeared in France, with the Goldsmiths’ Statute of 1260 promulgated under Etienne Boileau, Provost of Paris, for King Louis IX.
Assay offices did and do exist in the U.S., but they are affiliated with the government’s coinage mints and serve only the government’s purposes in that field. They are not involved in hallmarking, as there is no hallmarking scheme in the U.S.
In the 1800s, the functions of assay offices in the U.S. included receiving bullion deposits from the public and from mining prospectors in the various American territories. The assay offices that still operate today function solely within national coining system (including bullion coinage for sales to investors).