This ring has a cameo style purity mark that says 18C or possibly 18ct and a makers mark with the initials A H. They are capital letters, cameo style each in a diamond shape (square rotates angle down). The diamonds join slightly in the center. I was told the ring dates from the late 1800s to early 1900s. It has a quarter carat OEC diamond and tests as 18k gold.any info is appreciated. Thanks!