Help identifying hallmark and age of diamond ring

[Okaykate]

Hi all! Im new here so I hope I'm doing this correctly... So I know my engagement ring is old, but I'm not sure just how old it is. There is also a kind of x shaped marking with a line coming out of the top. I couldn't find anything similar in my search. Im not knowledgable on antique setting or stones so any info on that would be great! If anyone has any thoughts about the age or marking I would very much appreciate it!

 

[JPie]

Based on the "14K," style, and the modern round brilliant cut of the diamonds, I'd guess this ring is American and vintage '40s. There's a similar one on eBay: https://www.ebay.com/itm/VINTAGE-14...RCA-1940S-45ct-TOTAL-NICE-PIECE-/401382132677

 

[stracci2000]

I agree with @JPie about the time frame, 1940's or so.
It's very beautiful!

 

[Okaykate]

Thank you for the info! I have also had someone tell me it is not a modern cut because of the frosted girdles? Is that always true?