The underside of a Wedgwood plate, showing the diamond registration mark. The numeral IV in the loop at the top signifies the ‘class’ or material, in this instance ‘clay ware’. The letter V in the right corner is for the year 1876, the letter A at the bottom, for the month December, and, at the top, the number 5, for the day. This design, therefore, was registered on 5 December 1876. This particular plate may date after that year.
This mark, ‘Wedgwood & Co’, was used from 1860.