Before 1700 there was no systematic control over silver marking and it was only with Peter the Great that a "silver standard" was set and Assay Offices established in all major cities.
The standard for Russian silver is measured in zolotniks: the most common fineness is 84, corresponding to 875/1000 standard. There are also other standards that can be encountered, which include 88, 91, 94 and very rarely 96 (meaning pure silver).
Up to the late 19th century each silver item had to be marked, other than with the silver standard mark, also with town mark, Assay Master mark with date, and Maker’s mark.
Andre Carlovich Adler