Marquise Cut Lab Grown Diamonds Shop loose marquise cut lab grown diamonds at Luvia Designs. The marquise cut features a distinctive elongated shape with pointed ends that maximizes carat weight and creates a dramatic, elegant look. Our IGI-certified marquise lab grown diamonds offer brilliant sparkle and exceptional value. Browse our selection of loose marquise cut lab grown diamonds in a variety of carat weights and grades — ideal for unique engagement rings and custom jewelry designs.