If you want a halo setting specifically to make your centre stone look larger, choose one with diamonds of the same quality (colour, cut, and clarity) as the centre stone. “A contrast would pronounce the differences between the centre and accent stones and lose the desired effect,” he says.
You should also keep in mind that halo settings don’t have to be made up of diamonds. Patrick says that halo rings are great if you want to incorporate coloured stones in your setting, adding, “Many halo rings have beautiful emeralds, pearls, or rubies as the centre stone, which, design-wise, makes it more interesting.”
And while any cut works with a halo, a round diamond is usually the most popular option for perfect symmetry.