A beautiful piece.
A rarer coin in this state of preservation.
Obverse: crowned royal monogram in the pearl rim, in the rim legend:
POTIORQ3:METALLO EST, in outer rim legend: DAT:PRETIVM:SERVATA:SALVS-;
Reverse: in the pearl rim a crowned shield with the coats of arms of the Crown, Grand Duchy and Snopes, in the field of the shield the denomination XXX GRO/-POL-, on the sides of the shield the initials A-T, in the outer rim the legend:
MONET:NOV:ARG:R[]POL:1666;