Diagonal ring set Alice wore...

I don't know the designer, but it looked to me like a chevron or cross type of ring/set. Both are very nice, especially the double-ring sets. Hers could have been a variation on either style. Some people also call criss-cross rings "diagonal" rings. A word of caution...If you get a criss-cross/cross ring, don't get the kind that has the bands at a 90° angle unless you have huge hands. I ordered one in my size, but when I got it, it was way too big to wear comfortably. It's now a very expensive scarf ring. Lol
Do a Google search with the above tags, and you're sure to find something you like. Hope that helps!