Great Great Turquoise in a Navajo Sterling Silver Ring

Navajo sterling silver ring with dark green turquoise that has chert black matrix and white quartz inclusions. Unusual stone. The stone is set in a plain bezel and is embellished with twisted wire rope, large hand dropped raindrops and a feather. 

Size: 8 Shank is hand hammered and cold chisel split. C. 1970. No hallmarks. Acid tested.