Cubic Zirconia, is the cubic crystalline form of zirconium dioxide. The synthesized material is hard and usually colorless, but may be made in a variety of different colors.
Cubic Zirconia rates an eight on the Mohs Scale of Mineral Hardness, which is a scale from 1- 10. When your cubic zirconias are set into quality metals, such as gold, sterling silver, titanium, or platinum, they will retain their value and appearance for decades. So, Cubic Zirconia may not be expensive to acquire, but they last a very long time.
Due to its low cost, durability, and close visual likeness to diamonds, synthetic cubic zirconia has remained the most gemological and economically important competitor for diamonds, since commercial production began in 1976. Its main competitor, as a synthetic gemstone is a more recently cultivated material, synthetic Moissanite.