Is there an easy way to tell apart the 72% silver and the nickel varieties of the 1967 1 Gulden? My Krause shows 7m silver & 31m nickel made with the same date and apparently identical designs. The coin is magnetic, but I'm not sure if the 72% silver varieties are magnetic as well (I don't know what the 28% alloy is, and it might give a strong magnetic response too).
