This would be a Navajo ring. Looks like it could be variscite. It would be difficult to age, the best information comes from the seller if we believe him/her to be trustworthy.
it’s hard to ID older stones, especially when the piece is so small, because skin oils and time can change the color significantly from when it first came out of the ground. Cute little ring!
I have a ring of the same style. It was purchased new in the early 1980’s as Sleeping Beauty.
The stone was not stabalized. I have worn it a lot.
Over the years, the color has changed from the traditional blue to greenish.