Vintage Mexican Sterling Silver Dome Ring Size 6.75

Vintage Mexican sterling silver dome ring. It is a size 6.75. Hallmarked inside. Measures 12mm wide. Weight: 4.6 grams. 

This came to me from a man that found a large amount of rings on the beaches of Mexico and Southern California with a metal detector. The majority of them are from the 1970s and early 1980s.