Ancients: Gaius (Caligula) AD 37-41  AE Sestertius (35mm, 26.3 grams) 
Obverse: CaersarAVG GERMANICVS PON M TR POT, laurete head left.

Reverse: AGRIPPINA DRVSILLA IVLIA, the sisters of Caligula standing, bearing the attributes of various goddesses, Sc in ex.

This coin is unconditionally guaranteed authentic.   Send item # to NCG!!!!

See photo of a recent sale of a similar coin on heritage auction. That one had been smoothed-