Thermal conductivity: Diamonds are thermal conductors while cubic zirconia is a thermal insulator. This is what makes the diamond stand out next to the cubic zirconia with special instruments.
Hardness: Diamond has a rating of 10 and Cubic zirconia has an 8 on the Mohs hardness scale.
Density: Cubic zirconia is 1.7 times denser than a diamond.
Refractive index: Diamond has a refractive index of 2.42 vs. Cubic Zirconia has an index of 2.15-2.18
Cut: Diamonds are typically cut differently than cubic zirconia gemstones.
Dispersion: Diamond 0.044 vs. cubic zirconia 0.058-0.066
Color: Cubic zirconia is equivalent to the perfect “D” on diamond’s grading scale but it also comes in other colors as well, such as green, orange and pink, etc. Most diamonds on the other hand have a brown or yellow tinge to them, and only the rarest are truly colorless with diamonds.