Art Deco Sapphire Engagement Ring in PlatinumArt Deco Sapphire Engagement Ring in Platinum. This antique Art deco platinum setting features a round . 65 carat sapphire. The sapphire is a navy blue with great refraction of light and a violet tone. The sapphire is set in a platinum basket with split style prongs commonly referred to as a fish tail setting. The sapphire is accented by six (6) single cut round diamonds bead set into the channel shoulders of the platinum ring. The total side diamond