sylvia light brown cameo

by Sylvia
(Roanoke, LA)

I have a cameo that seem like it's been engraved inside the light brown stone, set in a pin with seems like a yellow gold setting. I've put a magnet to it, it doesn't pick it up. I've always been told if it's real gold a magnet won't pickup anything above a 14k gold. Can't find markings. Can you tell me anything else that would help if it was a real jewel or just costume. I recieved it for Christmas, but my sister always goes to estate sales, she doesn't know where she bought it from.