Oval Sapphire Diamond Engagement Ring 18k White Gold.  This incredible ring features a dazzling 3.53 carat oval cut sapphire and two (2) .26 carat round cut diamonds set in 18 karat white gold. The four prongs holding the sapphire give a bit of a dramatic look and contrast to the classic design of this beauty. Whether an engagement ring or a cocktail ring to be worn on the right hand, this one is sure to sparkle.