2.59 No Heat Sapphire & Diamond Engagement Ring in PlatinumA modern style of engagement ring to take your breath away! This elegant engagement ring features a 2. 59 carat oval sapphire and diamond accents in platinum. The royal blue sapphire has not been heat treated and is an exceptionally rare variety of sapphire, exhibiting the unique ability to change color when viewed under different light sources. It shifts from blue under natural daylight to a violet purple under incandescent light. GIA certified and