Intriguingly called 'Russian stone', and famed for the clarity of the glass, mirror-like polish and skillful faceting and carving, glassware from the Imperial Glass Factory was unrivalled during the Russian Empire period. The principal designer of the Imperial glass factory between 1819 and 1848 was Ivan Ivanov, who was responsible for most of the designs for coloured glass or crystal items executed for the Imperial family (N. Thon (ed.), St. Petersburg un 1800, Recklinghausen, 1990, pp. 395 and 398, no. 344).