This is a Sonora Sunrise (Sonoran Sunset) ring. The silver and been textured and oxidized to bring out the design. The band is textured and has a twisted wire trim.
The underside is stamped with the hallmark and marker's mark.
The measurements of the top of the ring is 1-11/16-inches by 1-1/16-inch. For wider bands, you usually need about 1/4 size or more larger.
NOTE: This is a semi-wide band, You will need to order about a 1/4 to 1/2 size larger than for a normal narrow band.