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.