I’m not a jewelry expert but the ring you’re talking about is marked .925 mex. I’ll just polish it a bit and add to to my collection. Thanks for the likes!Congrats on a great water hunt & the rings! That large honker with the diamond should be tested for gold even if there are no markings. Test the diamond also. It looks like a ring that may have been custom made for someone a long time ago.(IMO)
Also, you could sand the inside of the ring with fine, 600 grit wet/dry sandpaper but leave the rest of it unpolished. The contrast & the age would make it stand out. Nice find !!