Lab-grown diamonds reminiscent of a star-filled sky create this circle necklace, centered with a rich blue lab-created sapphire drop in a star setting for otherworldly sparkle. Sterling silver 3. 4mm blue lab-created sapphire center drop graduating sizes of lab-grown diamonds f color/vs2 clarity 7/8 ct. T. W. Lab-grown diamonds 16. 0- to 18. 0-inch adjustable cable chain; lobster claw clasp from the stellar star collection exclusive to zales