it looks like .875 silver (84 Zolotniki) with a for me unknown Kokoshnik / silver mark, perhaps 1885 if I read it correct.
Some more info :
https://www.silvercollection.it/russ...allmark1b.html
https://www.925-1000.com/Frussia_kokoshnik_01.html
but some of our Russian specialists can advise in more detail