That is pretty. Try the site above for compatibles. Huge deposits of these found in Brazil. Values placed are all over the range depending on if you are at a high end retail or an off the beat rock shop. Something is only worth what people are willing to pay. Christmas on e-bay is probably your best resell option. Would also place it under collectibles in Craigs List.
Maybe you should take it to a jeweler to have it looked at. I’m not sure what it’s worth but it’s pretty! Good luck!
I think yoiu should have it reevaluated. True amethyst doesnt grow in setting like you have showing. They grow on the inside of mineral cones. I’m not sure what you have but it could be more valuable than amethyst.