Cubic Zirconia Masters for Diamond Color Grading | Advantages Disadvantages
CZ (Cubic Zirconia) masters are ok to begin with, but are not recommended for long-term use or for more expensive trading. It has been said that they darken over time, from which you could imagine the potential harm that could result. The other drawback is the difficulty in comparing the two different substances (CZ versus diamond). CZs reflect and refract differently and have a subtle difference in overall appearance, even to the naked eye.