Good question - more than half the gold and silver I find is unmarked. In this case, the ring is bench jewelry, probably made somewhere between 1960 and 1980. The overwhelming majority of unmarked gold I find is fine benchmade jewelry. Bench jewelry is one-off and made at a “bench” (lol) with hand tools, usually a torch, and a polishing medium. Many bench jewelers also do their own lapidary (almost certainly not the case with this ring). Bench jewelry is often unmarked or poorly marked (simply because it’s difficult to get a good strike on a completed piece and premarked components sometimes become illegible during assembly.)
It takes a while, but if you handle enough gold, eventually you will be able to spot it from a mile away. On this particular piece there were a number of giveaways: 1) color, luster and weight - these are unmistakeable and really just come with experience; 2) signs of malleability - micro dents and scratches, including hard file marks up inside the band; 3)the type and quality of craftsmanship - for example, the rectangular prongs are hand cut with a toothed band saw. Under a 10x loupe, you can see the tooth marks and the slight change overage where the jeweler went too deep. Very unusual to see that amount of time put into a non-precious metal piece.
All that said, I of course tested it. It falls somewhere between 18k and 22k.
