Large Turquoise Ring with Overlay Decorated Band Size 8 Sterling Silver

Vintage Navajo sterling silver ring set with a large turquoise stone with two tone color. It may be turning green. The shank is unusual in that it was created with the overlay technique and has a geometric pattern. 

Size: 8 Face measures 1 1/2" by 1 1/4". Weight: 14.4 grams. Marked 925. No Indian hallmarks. C. 1940.