An exceptional Art Deco Sapphire and Diamond RingAn exceptional Art Deco plaque shaped ring featuring a striking cushion cut natural sapphire of mid to dark blue hue, measuring approximately 9 8 mm and estimated at 3. 66 carats. The sapphire is set in an elegant millegrain platinum bezel, displaying natural inclusions visible only under 10 magnification characteristic of genuine stones from the period. The rings head measures 21. 6 15. 6 mm, with a depth of 5 mm, and is beautifully accented by