What are the diamond rings with 4 stones called?

My friend has a princess cut engagement ring that has 4 stones together that create a “solitaire”. What are rings like this called if I am trying to find them on the internet? I tried “4 stone ring” but that didn’t seem to be right. I guess they are probably cheaper than a real solitaire diamond but give the same effect.
I guess I didnt explain it well. They are 4 smaller diamonds grouped together to give the impression that it is a larger 1 stone solitare.
Also…any idea where I can find them, online or stores? I am cant seem to find them online

It’s called a quad-cut. They are quite popular right now and allow you to purchase a larger looking stone although it is really four stones together. Mine is a quad cut, but you can hardly tell unless you look closely.

Real Solitaire Diamond
Real Solitaire Diamond
Real Solitaire Diamond