Hi Jac777! Sorry to hear about your loss. I'm going to try and help you with your 6T. I also have a Prizm 6T. As I've had some good luck with my detectors I've been able to pick up some white gold items. So I scanned them with my 6T and they all rang up in the VDI- 06 to 10 and showed on the foil icon.
I would suggest you discriminate the first two items on the screen, iron and nails. Dig everything that shows foil. Now I have no idea what your ring will ring up as but it will probably be in the foil range. But, you can't ignore pull tabs, and zinc pennies. Gold does show up in that range also.
Have you been able to figure out how to work your machine? And did you get headphones? They will help. Run it with tone id. on and practice listening to the tones by running foil, pulltabs, coins so you can learn the tones. You may get overwhelmed a bit with the tones if the spot is really trashy so keep watching the screen for the icons. If you think it's on the surface you probably won't need the sensitivity too high.
Good luck. Let me know how you make out. You can pm me if you need any more help. The Prizm 6T is a good machine. It should find it with no trouble at all.