A nicely preserved piece with good details.
On the obverse the initials of Nikolai Grachev - mincmaster of the St. Petersburg mint.
Obverse: crowned eagle of the Russian Empire, on the sides of the tail the initials H-Г, in the rim the legend:
ЧИСТAГО СЕРЕБРА 4 ЗОЛОТНИКА 21 ДОЛЯ;
Reverse: in laurel and oak wreath crowned inscription:
МОНЕТА/РУБЛЬ/1841 С.П.Б.;