2 Carat Halo Diamond & Sapphire Engagement Ring2 Carat Halo Diamond Sapphire Engagement Ring. This incredible engagement ring features a 2 carat old European cut diamond in the center with a halo of sapphires. The center diamond weighs 2. 07 carats and is a J color with a VS2 clarity. The diamond is accented by a halo of French cut sapphires that provide a gorgeous contrast of color. Finished in platinum, this striking ring is eye catching from every angle.