Since you are making an expensive purchase, given below are three factors that you should note before buying a tanzanite diamond ring, as these traits influence the quality of the stone greatly.       Color Tanzanite changes color according to light. Under fluorescent light, it appears blue, while it appears violet under incandescent light. In addition, red and brown shades can be seen too. If you want a high-quality tanzanite ring, you can opt for a dark violet or deep blue stone. Durability You can buy a tanzanite ring only if you do not wish to use it for everyday wear. This is because the hardness of tanzanite is only 6.5 to 7 on the Mohs’ scale. You also need to look for any visible cracks, chips, and other flaws in the stones before buying a tanzanite diamond ring. Clarity When it comes to clarity, you have Type I and Type II tanzanite stones. In Type I, the tanzanite gemstone is very clean and has no inclusions, while on the contrary, Type II tanzanite has obvious inclusions. This leads to the fact that Type I will be a more expensive buy.