A very nice piece.
Obverse: bust of the emperor in radial crown, armor and paludamentum, to the right, in the rim legend:
IMP CAES M ANT GORDIANVS AVG;
Reverse: Emperor standing left, holding patera over altar, surrounded by legend:
P M TR P II COS P P;
Silver, diameter 23 mm, weight 4.93 g, axis 12 h.