I would like to know if this cameo ring is a good one and if it has much value

I have a cameo ring and I do know that it is shell and it is set in 10kt gold. To me it has a very nice setting. I would like to know if this is a valuable piece and around what time period it is. It has some a maker mark on the band but I can't tell whether or not it is wrc or hrc or if its honestly any of those letters. I am using a loupe but the mark isn't the easiest to see.