Estate Natural Diamond Halo Engagement Ring. This estate engagement ring is crafted in 18 karat white gold featuring a .86 carat natural round brilliant diamond center. The natural round diamond has SI2 clarity and IJ color. There are natural round brilliant cut accent diamonds pave set in a halo style frame around the center diamond, down the shoulders of the ring, and in the undergallery. The total weight for the accent diamonds is .66 carat. The halo diamond engagement ring weighs 5.79 grams and is a size 6.