Interesting! Quite possible since her ring has a similar setting to this other JAR string ring, see picture
The only thing that's making me wonder is the setting of Gwyneth's ring, particularly the base and the raised section in between Gwyneth's diamond and the band, which you can see more clearly in the picture below.
Mr. Rosenthal is famous for his "invisible" settings unlike Gwyneth's ring. That's a very chunky, thick obvious base which I've never seen in his ring designs. And not sure why there is a raised section there, seems unnecessary in the design (in the JAR picture I posted above, there is a double pave setting to hold the big diamond in place so there is function to the design.)
JAR usually likes to have very thin flat settings or a very flat base - not just on his rings but on his brooches and even bangles. He tends to like the base to be flat and thin because he supposedly likes the design to look like it's floating on air (but you're not supposed to see the setting or the base!) And that kind of aesthetic really highlights his excellent workmanship because you need to have superb skills to make a very complex design look "light" so the jewels look like they are floating on air (does that make sense?)
However looking at Gwyneth's pic again, the pave part is thin enough that is could look like JAR?
I am asking because I think that diamond stone is a Ashoka cut and William Goldberg specializes in them and he supplies JAR with stones. Also Gwyneth is a customer of JAR and that "ruby" ring on her finger looks JAR as well.
Another question is Lauren Santo Domingo a client because her engagement ring looks JAR.
