2.60 Sapphire & Diamond Engagement Ring in Platinum2. 60 Sapphire Diamond Engagement Ring in Platinum. This exquisite engagement ring features a 2. 60 carat blue sapphire and 1. 06 carats of diamonds finished in shimmering platinum. The center sapphire is a deep, royal blue stone that is emerald cut. The elongated facets on the stone create a beautiful hall of mirrors effect, giving light room to move and play within the stone. The sapphire is prong set and accented by a collection of near colorless