Watch List notes:

Anonymous, 1/3 Siliqua, Constantinopolis, c. AD 330; AR (g 1,05; mm 12; h 6); Pearl-diademed and draped female bust r. (Helena ?), wearing earring and necklace, Rv. K within border of dots. RIC -; C 287 (Constantine II); Mazzini 287; Bendall RN 158, 2002, 4.
Very rare, minor peeling, about extremely fine.