Given that this piece of coral came from the Aurora mine matrix, it means that the stratigraphic context is difficult to discern (sediments get jumbled during the overburden removal process). Therefore, it could be Miocene to Early Pleistocene in age. As to identification, it looks like the coral genus Solenastrea, which is found fairly frequently at Aurora.
@lcone – What do you think? Am I in the right ball park?