Vintage Mexican Biker Ring in Sterling Silver

This is a rare find. I have three Mexican biker rings that were brought to me from an estate in Mexico by a Mexican picker. This is one of those rings. 

This ring is a rare find in that the owner had it custom made in sterling silver. It is solid. Design is an Indian Chief's head in profile. 

Size 10 1/4, weight 28 grams. Face measures 7/8" x 3/4". 

It once had turquoise mosaic inlay in parts of the design. There is only a small piece left in the ear area. It is not hallmarked. I acid tested it and it is sterling silver.