Round halo engagement rings are one of the most popular settings and shapes. A halo setting is basically a cluster of diamond accents around the round diamond. The round cuts are romantic, but when you add them to a halo setting, it stuns the viewer with its double sparkling effect. This setting is also considered cost-effective, as the halo around your diamond makes your diamond appear larger than its actual carat size, so you can get a smaller carat size without worrying about it looking too small.