How can I date Belleek using the official marks?

Belleek provides an official dating guide using numbered trademark periods. The 1st mark runs 1863–1891, the 2nd 1891–1926, the 3rd 1926–1946, the 4th 1946–1955, the 5th 1955–1965, the 6th 1965–1980, and the 7th 1980–1993. Later periods include blue marks (1993–1997 and 1997–2000), a Millennium 2000 mark, and later green/brown updates leading to the 2019+ mark. Start by finding the stamp, then compare the full graphic—text, ribbons, symbols, registry letters, against the official images and date bands.