What is this cut style?

by Caitlyn
(Spokane, WA)

I found this in a vintage/thrift store and just fell in love with it. Once I got it home, I realized how filthy it was. After a gentle cleaning I realized it was a tri-colored stone...but what I love the most is how the stone is cut with the scallops? along the edges. I don't even know what the stone is, I just love the ring. It is marked 925 up inside, so at least I know it's silver. Can anyone help with the type of cut? In the one picture, there is no blue in the stone, I was using the light to reflect the edges. The stone is just green and yellow with a white streak through it.