Vintage handmade ring -adjustable band currently size 6

The Centerstone on this ring is large. It has an iridescent, purple and garnet and red in it. I am not sure what this is but it’s very cool and I have gotten a lot of compliments on it when I wear it. it is about an inch long. I wear a size 6 and it fits me. I have no idea how this ring is but I have had it for probably 45 years and I bought it at a consignment store.