In Claddagh Design all our jewelry bears an our own unique Irish hallmark (Check out that link for a lot more information). This means that all our work has been independently tested and stamped with the mark of the Irish Assay office. The only Assay office in Ireland is based in Dublin castle and has been testing and hallmarking precious metal since 1637. We stamp our makers mark on the item of jewelry. This stamp has the initials of the maker and as no two makers marks are the same, the work of any jeweller can be traced. Then we send it to the Assay office where they test the purity of the metal. Once they are satisfied that the metal is of hallmark quality they add the remaining stamps to the hallmark. Here is a diagram of the various Irish hallmarks available.