Cubic zirconia (CZ) is the most readily available, inexpensive and brilliant simulated diamond on the market today. Cubic zirconia does occur naturally in small quantities, but all of the cubic zirconia on the market is produced in a laboratory.

On the Mohs Scale, which measures the hardness of minerals, cubic zirconia is an 8.0 to 8.5. Ruby, sapphire and diamond are all harder substances than cubic zirconia, but cubic zirconia is still very durable. It is important to understand that hardness is not necessarily related to durability. Even though diamond is the hardest mineral (10.0 on the Mohs Scale), it can still be chipped or broken.

The only ways to tell the difference between cubic zirconia and diamond are by use of a thermal probe, by weighing the loose stone or by microscopic examination of surface features and inclusions. Cubic zirconia weighs approximately 65% more than diamond. Therefore, while a 6.25 mm round diamond weighs about 1.00 carat, the same size cubic zirconia weighs about 1.65 carats. If you know the weight of a cubic zirconia, you can figure out the diamond weight equivalent by multiplying the cubic zirconia weight by 0.6, or 60%.

Glossary

Brilliance: The white light leaving a jewel, traveling upward, which is visible to the eye. Brilliance is sometimes referred to as “sparkle.”

Dispersion: Flashes of rainbow colors. Also called “fire.”

Hardness: Resistance to scratching. The higher the number, the more resistant.

Luster: The shininess of a jewel.

Toughness: Resistance to breakage.