This lovely Ptolemaic scuplture may represent the last pharaonic ruler of Egypt, Cleopatra VII, an earlier Ptolemaic queen, or it may be an image of the goddess Isis.  The back pillar, which often bears an identifying inscription, is blank, and the crown, another identifying characterisitc, has been broken. 

Whether it is the queen or the goddess, it is unlikely to be a careful portrait of any particular human face.  It is a pleasant, generalized rather stodgy image of calm femininity.