A very rare denarius, without a mark in the crown. Characteristic crown with circles in the rim, not seen on other types of denarii of this ruler. According to Gregory Romanczyk, the type of denarius minted in 1526 and early 1527
http://blognumizmatyczny.pl/2020/03/13/grzegorz-romanczyk-denary-koronne-zygmunta-starego/ Type appreciated by Kopicki with the degree of rarity R7. No numerical note due to being minted in coinage silver, which was treated by NGC as an oxidized surface. A beautiful denarius, a sought after numismat!