A beautiful, periwinkle piece with nearly gearless detail.
Background flaws.
On the obverse visible initials НФ - Nikolai Follendrof holding the office of Mincmaster of the St. Petersburg mint several times.
Obverse: an eagle of the Empire of the 1832 pattern, between its legs and tail the initials НФ, in a rope border, in the outer border an inscription beginning with a rosette:
ЧИСТAГО СЕРЕБРА 4 ЗОЛОТНИКА 21 ДОЛЯ;
Reverse: in a laurel and oak wreath crowned inscription:
РУБЛЬ/1878/СПБ;