1 Drachma (1966-1973) (type unknown) uniface mint error in trial strike in copper instead of copper-nickel with "ΚΩΝΣΤΑΝΤΙΝΟΣ ΒΑΣΙΛΕΥΣ ΤΩΝ ΕΛΛΗΝΩΝ". Weight: 2gr. Inside slab by NGC "MINT ERROR MS 64 RB - STRUCK IN COPPER, UNIFACE OBVERSE". (Hellas 220-224). Rare!