GMco

by Yvonne
(Cypress, CA, USA)

Mom passed away 2 years ago. My sisters and I just recently had the strength to go through Mom's cedar chest. In it, we found what appeared to be a 1940's style engagement ring that none of us knew anything about. We are calling it Mom's Mystery Ring. 14k yellow gold, white gold around the diamonds, largest is 1/2 karat. The stamp inside is G M Co. What does this mean?