4.16 GIA No Heat Sapphire Engagement Ring 14kThis three stone engagement ring features a GIA certified 4. 16 carat no heat blue sapphire from Sri Lanka, set in 14 karat yellow gold and flanked by trapezoid cut diamonds totaling . 38 carats. "No heat" means the sapphire's color is entirely naturalit hasn't been treated or enhanced, which is uncommon for stones of this size and quality. The octagonal step cut shows off the sapphire's color in long, clean flashes of light rather than sparkle,