This is a Strell (marked on inside of band) 14 KT yellow gold ring. I'm not sure what the stone is...could it be a fire opal? The total weight of the ring is 6.8 grams and it is probably a size 10. I'm not sure what year it was purchased...probably at least 30+ years old. One side of the setting has a flower with a diamond in the center and the other side has a figure of a woman holding up the larger colored stone.
As far as I know, my father purchased this for my mother probably some time in the 1970's or 80's.
Dear Virginia - This ring is simply fabulous. It was designed by Strellman, who sign their work Strell and are known for dramatic and unique settings. I've had the pleasure of handling Strellman pieces before. While this looks like a fire opal, it's actually a lab created Padparadscha Sapphire, something Strellman is known for being the originator of.
The last piece I am aware of which sold at auction sold in the range of $300USD, it did not have a diamond but did have a larger center stone, because of this I would expect yours to sell at auction in the same range of $300USD to $400USD.
If you have any follow-up questions, please let me know and thank you for submitting to Mearto.