Province: Asian.
Asian gem stone archer thumb ring.
Similar rings were used Archery in south East Asian countries.
It is also called as ZEHGIR in Persian language and in Turkish it is called SHAST"and other name is HORSEARCHERS , different countries have different names of similar stone ring.
Similar rings were used in many countries like Turkish , Ottoman , Roman, Mongols ,Mughal & Indian.
In central Asian such thumb rings are integral piece of equipment of Archery.
This would be fine addition to your collection.