You mean their Elsa Peretti fixed bezel pendant? IMO that doesn't look like floating at all ... because bezels usually look more chunky (as they are beefy for everyday wear).
If she wants a "floaty" look, get her a 3 prong martini. Just about anybody would be able to duplicate these looks.
I'm a Brian Gavin stan, so you can check them out. Platinum seems the way to go if you do a 3-prong martini since the stone's going to be at risk of falling out. And make sure you ask for a nice wooden gift box. lolol.