Marked with 56 zolotniks gold standard (14K - 583) / St
Petersburg assay office 1908-1917, and maker's initials Cyrillic 'ЗБ'.
There were two jewelers with these initials, known
to work in St Petersburg in the corresponding period - Zalman
Bogorad (recorded in 1916) and Zalman Back, owner of a gold and
silverware shop, mentioned in 1906 (see A.Ivanov Gold And Silversmiths In Russia
1600-1926, Nr. 283 and Nr 476).