18ct white gold Pledge ring set with a 4mm round white diamond.
I have reduced the bowl size of the Pledge ring to fit the smaller stone.
I usually set 6.5 -7mm round stones in the Pledge rings.
I also delivered to e.g.etal the week before a beautiful Pledge ring in yellow gold set with a 7mm round natural Australian parti sapphire. This is a really special blue/teal stone. In my haste to get it finished and delivered I forgot to photograph it so have no images of it. So it need to be seen to be believed!