Must be the maker mark. Ring has little to no flaws and the Letter'A' retains a lot of original detail. This ring seems to be either from the Victorian Era or Mid Century Modern area (40s/50s). There is also a small screw that connects the Onyx to the shank. Shows you how old this ring is!To the left and right of the Squre Onyx Stone there is either White Gold or Silver along side the 10K Gold. Seeing that the stamp doesn't say Sterling + 10K, so I believe its Yellow 10k Gold with White Gold 10K (Don't quote me on that).
The item "Vintage 10K Gold Old English Font Letter Initial'A' Onyx Mens Signet Ring" is in sale since Wednesday, August 4, 2021. This item is in the category "Jewelry & Watches\Vintage & Antique Jewelry\Rings". The seller is "avsalesinfinite" and is located in Whittier, California. This item can be shipped to United States.