50 Dollars - Elizabeth II Steffi Graf

Niue began issuing collectible silver dollars in 1987 under a licensing arrangement that allowed the tiny Pacific island territory to generate revenue through commemorative coinage — a program with essentially no relationship to local monetary circulation. The Graf piece appeared the same year she turned professional and won her first Grand Slam title at Roland Garros, making the timing unusually prescient for a commemorative issue.

The .625 fineness is notably lower than the .999 or .925 silver used by most contemporary commemorative programs, a deliberate cost-reduction measure that kept production margins favorable for the issuing authority.