A letter G within a lozenge or diamond shape | Gold Diamond Ring

by Daniel
(Waco,TX, USA)

I have a scottish rite gold diamond ring, it is makerd 14K. Next to the hallmark there is a makers mark, there is a letter G within a lozenge or diamond shape. Some thig like this but enclosed, please see picture.

My best guess is the diamond shape is a maker's mark or assay mark, and the letter G is part of maker mark or is a time/year letter, which would be I guess 1957.

I can't confirm any of this if you can helps thanks a lot.
Dan