Wow that’s a HONEY of a stone! Yum!
It would be helpful to see a side view of the setting to determine origin. The outer bezel appears to be a pressed roll, rather than a ridge built atop a flat platform sheet of sterling which indicated US and Middle American design. The only older pieces that have a similar look are a subset of Zuni that have a roll around the edge, but it is still built on a platform and you scan see the joint where the thin silver roll was draped around the edge.
Note the joint at the bottom of the outer ridge on this very old Zuni piece.
Generally though, a thicker uncut base layer with the bezel pressed into it would indicate Persian silversmithing where they have some of the equally excellent turquoise mines in the world, many still in production. (India bezels are usually raised like clear stone settings to let light in or give the stone more prominence.) Also the rounded edge seen from the back, rather than a cut plate, and the dimple along where the bezel was possibly pressed a bit too deep in one spot are also indicators.
I have bought several Persian pieces in NM & AZ shops of high regard, that were just to pretty to shun based on location. Trading posts buy mixed lots for resale and invariably there’s global pieces mixed in. Similarly, many of the dealers and trading posts in the Southwest US have even begun farming out their branded inlay designs to be made in the Philippines as demand outstrips the supply of native hands and mines for production.
This is one I have to get better shots of, but I can’t get my daughter to take it off!
The picture does not do it justice because of my tons of turquoise this is one of the most hypnotic stones in the stack!!! Turns heads across the room!