Black Cameo Ring

by Kathleen

I have a man's ring, which may be considered a cameo. It is a gold ring, wih a black stone. The stone has a carving of a woman. I am trying to determine if the ring has any value, and how old it may be. Can anyone help me determine what this ring might be worth? Or how old it is?

There is a small chip in the bottom of the stone, which I know will decrease it's value. The third picture shows the chip.