A nice piece.
Variant with a fan-shaped eagle tail.
Injuries to the background.
Obverse: crowned eagle of the Russian Empire, on the sides of the tail the initials M-W, in the rim the legend:
ЧИСТAГО СЕРЕБРА 4 ЗОЛОТНИКА 21 ДОЛЯ;
Reverse: in laurel and oak wreath crowned inscription:
МОНЕТА/РУБЛЬ/1846;