Vintage Southwestern handmade silver tone ring with blue turquoise, size 3

Vintage silver tone Southwestern ring with blue turquoise stone. Handmade. Size 3. in excellent condition, with some vintage patina (I can clean it upon request). Not stamped. Looks like sterling silver, but can't say for sure. The stone looks like natural turquoise, but also not sure how to authenticate it. So selling as is.