What kind of setting is this, and how is it done?

[JaneDoe]

I have come across jewellery with stones set in an interesting way. I like it a lot, but can't find anything about how it's done. I don't know if it's because it's not very popular or because I don't know what keywords to use.

Photos attached.
I can only think about gluing the bezel (?) to the stone.
The photos are of rather expensive jewellery. While I assume it might not be done in a traditional way, I'd think the setting is at least somewhat strong/long lasting.

As an aside, would using glue generally be a good idea for such non traditional settings? I have seen other settings where there doesn't seem to be any metal actually holding the stone. I'd like to experiment with ways to expose more stone or present it in a more creative way, but I don't want to make something that's going to break right away.

I'd really appreciate any help!