Nice piece, well-preserved details.
Obverse: crowned eagle of the Russian Empire, on the sides of the tail the initials M-W, in the rim the legend:
ЧИСТАГО СЕРЕБРА 1 ЗОЛОТНИКЪ 5 1/4 ДОЛЕЙ;
Reverse: in laurel and oak wreath inscription:
25/КОПѢЕКЪ/50/GROSZY/1846;