Vir Jewels Genuine 6 Stone Tanzanite Cuff Bangle 0.40 CT 30 Day Easy Returns. Jewelry Gift Box Included Rhodium Plated Brass Natural Tanzanites are heat treated to produce a range of hues between bluish-violet to violetish-blue. This is done through mild heating in the production process. Due to the permanent nature of this treatment the gemstones do not alter in quality, only in appearance.