In addition to the current Czech brands (see picture above), all hallmarks that have been valid in the history of Czechoslovakia and did not express lower purity than the lowest purity for individual precious metals listed in the Hallmarking Act (§3, para. 2) are valid. Thus the Austro-Hungarian, Czechoslovak, Protectorate and Slovak state brands. An example is the hallmark called the lapwing, used until 1993 for the purity of 585/1000, which you can see by clicking here. However, the hallmarks that were introduced in the Czechoslovak territory occupied by foreign states (Austrian, Polish and Hungarian brands) during World War II do not apply. Other valid historical marks are published in the brochure of ing. Bouš, “List of hallmark marks valid in the Czech Republic”, first published in 2008, supplemented by the 2009 edition.
The Czech Convention on the Control and Labeling of Precious Metals (the so-called Vienna Convention), which the Czech Republic acceded on 2 November 1994, also applies in our territory, see http://www.hallmarkingconvention.org/. Representations of Czech conventional brands can be found here, other Member States of the Convention have their conventional brands similar.
Following the accession of the Czech Republic to the EU, the hallmarks of some EU member states were gradually recognized. As of the date of this text update (6 January 2016), these are selected hallmarks of Estonia, Finland, Croatia, Ireland, Cyprus, Lithuania, Latvia, Hungary, Malta, Poland. , Portugal, Slovakia, Slovenia, and the UK. Current state, more detailed interpretation and depiction of recognized hallmarks can be found after clicking on this inscription: Recognized foreign hallmarks.
In connection with the establishment of a number of new workplaces of the Assay Office, it became necessary to distinguish the hallmarks between individual workplaces in miniature letters: P-Prague, J-Jablonec nad Nisou, B-Brno, O-Ostrava, T-Turnov, R-Tabor Pilsen, L-Olomouc, H-Hradec Kralove, K-Cerveny Kostelec. These letters are situated close to the fineness number and are oriented perpendicular to the vertical axis of the mark, which distinguishes marks stamped by the Assay Office of the Slovak Republic, whose otherwise identical marks contain miniature letters oriented parallel to the vertical axis of the hallmark. This distinction is introduced gradually, existing brands are used until stocks run out. Goods shall be deemed to have been properly armored regardless of the workplace or the authority designating them, and no further examination or marking is required.