Here the vivid violet-blue hues of tanzanite shine brilliantly against fine white gold and a halo of sparkling, sustainable lab grown diamonds, creating a look of exquisite luxury. Tanzanite is the beautiful birthstone for December and is known for its stunning shimmer, which changes hue depending on how the light catches it. *The sustainable luxury choice. Lab-grown diamonds are chemically and optically identical in brilliance and beauty to a natural mined diamond.