Within a group of nations which are signatories to an international convention known as the Vienna Convention on the Control of the Fineness and the Hallmarking of Precious Metal Objects, additional, optional yet official, marks may also be struck by the assay office.
These can ease import obligations among and between the signatory states.
The Master Craftsman was responsible for the quality of the work that left his atelier or workshop, regardless of who made the item.
Hence the responsibility mark is still known today in French as le poinçon de maître literally "the maker's punch".
The multi-tiered motif of the CCM is the balance scales, superimposed, for gold, on two intersecting circles; for platinum, a diamond shape and for silver a mark in the shape of the Latin letter "M".
Thus, a stamp of '925' by itself is not, strictly speaking, a hallmark, but is rather an unattested fineness mark. if metal fineness is claimed, even though there is no official hallmarking scheme in that country.
Similarly, with the consent of all the current member states, the terms of the convention may be amended.
The most significant item currently up for debate is the recognition of palladium as a precious metal.
Many nations require, as a prerequisite to official hallmarking, that the maker or sponsor itself marks upon the item a responsibility mark and a claim of fineness. Nevertheless, in nations with an official hallmarking scheme, the hallmark is only applied after the item has been assayed to determine that its purity conforms not only to the standards set down by the law but also with the maker's claims as to metal content.
In some nations, such as the UK, the hallmark is made up of several elements, including: a mark denoting the type of metal, the maker/sponsor's mark and the year of the marking.
Other nations monitor the activities of the Convention and may apply for membership.