2.5-3mm Cultured Pearl, Diamond Lariat Necklace In Gold. 24" Our necklace's stylish lariat design threads a strand of 2.5-3mm cultured freshwater pearls through a .15 ct. t.w. diamond-dusted circle; position the circle anywhere along the strand to change the look as you like. A larger 7-9mm pearl drop is the finishing touch. 14kt white gold. Pearl birthstones are the perfect gift for June birthdays.