The differences between cubic zirconias and diamonds include cost, color, hardness, material, density, dispersion and use. Cubic zirconia is commonly referred to as CZ, and it is a crystalline form of zirconium dioxide. Cubic zirconia is a synthesized material, whereas a diamond is the hardest natural material known to man. Although cubic zirconias and diamonds share adamantine luster, the characteristics of each stone are significantly different.
The price of a cubic zirconia is low in comparison to the more expensive diamond. A cubic zirconia is synthetic and can be made colorless, while diamonds generally have a hint of brown or yellow. Colorless diamonds are rare. Cubic zirconia is used primarily as a gemstone, while diamonds have a number of uses, including in jewelry, for industrial purposes and as cutting tools.
Diamonds are much harder than CZ. Diamonds have a Mohs of 10, while CZ is an 8.5 on the Mohs hardness scale. The dispersion of CZ is higher than that of a diamond. CZ dispersion is 0.060, whereas a diamond has a dispersion rate of 0.044. The crystal system of a cubic zirconia is tetragonal, and a diamond is hexoctahedral. The refractive index of CZ is 2.176, while diamonds have a refractive index of 2.147. This has a direct effect on how light reacts with the stone. Cubic zirconia is a thermal insulator, and diamonds are thermal conductors. The specific gravity of a cubic zirconia ranges between 5.6 and 6, which is about 1.7 times more than the specific gravity of a diamond.