Oval Cut Sapphire w/ Diamonds Engagement Ring in 18kOval Cut Sapphire w Diamonds Engagement Ring in 18k. This dazzling engagement ring features a 2. 71 carat oval cut sapphire flanked by two gorgeous asscher cut accent diamonds and finished in 18 karat white gold. The dark blue sapphire is claw set which creates a nice icy contrast of colors above the brilliant asscher cut diamonds. The shank is simple, keeping all of the attention on the amazing center stones.