#1 is something I've always wondered about, but haven't thought
about for years... I think the gold ring is probably stretched up
inside the jade ring. Either that or some kind of die forming
1.) A ladies wedding band about 2-3 mm wide with a strip of
apple green jade set in the center all the way around. Gold,
jade, and gold.
regarding #2 below, I've set quite a few stones into other
stones. It's pretty easy, and even easier if you can lathe a
bezel and tube to fit. I always set the small stone into the
bezel first, and then fit that into the main stone as seamlessly
as possible. You can set flush, on top, or whatever. I have used
diamond drills and created various shapes of pockets to put
stones into, such a baguettes, marquise, princess, etc...
working carefully, you can create any shape pocket you want. I
have then melted wax or plastic into the pocket and created a
bezel from that. the fit is incredible.
Good luck, have fun!