Russia, Nicholas I, Rouble 1840 НГ

A very nice piece with a well-preserved luster in the background. Coin with initial of Nikolai Grachev.

Obverse: eagle of the Empire of the 1844 pattern, between its legs and tail the initials НГ, in a corded 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:
MOHETA/РУБЛЬ/1840/СПБ;