Phenomenal mint piece - date punch not caught by NGC.
A very rare coin in such excellent condition.
Obverse the eagle of the Empire, at its tail the initials НГ, in the outer rim the legend:
ЧИСТАГО СЕРЕБРА 6 ЗОЛОТНИКОВЪ 31 1/2 ДОЛЕЙ;
Reverse: in laurel and oak wreath inscription:
1 1/2/РУБЛЯ./10/ZLOT-/1835;