Jewelry - Cut Gemstone bezel mount

[Ben Nelson]

Hello!
I'm working on a jewelry project. I plan to mount an oval 12 ct. cut Amethyst into a bezel-mount to make a pendant.

Our wedding anniversary is coming up, and this loose stone belonged to my wife's dearly departed mother. So, it has some sentimental value. It's too big for a ring (18mm x 13mm oval cut,) but would probably make a pretty nice pendant.

Most of her jewelry is silver color, and working with actual silver sounds like a good approach. 

At this point, I'm planning to order something like this: https://www.firemountaingems.com/7246FX.html
An open-back bezel drop. I think I should just be able to place the amethyst in it and fold over the bezel edge.

I found some costume jewelry at a rummage sale and noticed a piece which had two ovals that matched the size of the amethyst. I bought it and worked the part out, filed it, etc. It was something like zinc or some other base material with copper-plate over that and then nickel or silver over the copper.
On the costume jewelry, the (plastic) "stones" were simply glued in place, so I didn't have an actual real bezel edge to bend over. Still, as just a mock-up, it worked pretty well. 

Any advice for somebody who has never made jewelry before?
I really just want to take the simplest approach possible to mount the stone and make something she would wear.

Thanks!
-Ben Nelson

Here's some photos of the actual gemstone and working with some costume jewelry as a mock-up.

note

 The open back of the actual silver bezel should be more open than this piece of costume jewelry, so the stone sits in it deeper. (Plus no ugly lines on the back.)