RUSSIA. Duo of Silver Denominations (2 Pieces), 1849 & 1861. St. Petersburg Mint. Both PCGS Gold Shield Certified. 1) 10 Kopeks, 1849-CNB NA. Nicholas I. PCGS Unc Details--Tooled. KM-C-164.1; Bit-373. Eagle of 1845-48.<p>2) 25 Kopeks, 1861-CNB OB. Alexander II. PCGS AU Details--Tooled. KM-Y-23; Bit-135. A <strong>KEY DATE</strong>, and <strong>VERY RARE</strong> and desirable no matter the details designation.