Q&A - What is Cubic Zirconia (CZ)?

Cubic zirconia is an inexpensive diamond substitute. Also known as CZ, cubic zirconia is synthetic, which means it is created in a laboratory. Commercial production of CZ began in the 1970s.

Terms used to describe substances that are used to mimic another are faux, fake, imitationand simulant, but cubic zirconia only becomes a problem-purchase when it is misrepresented as a diamond or other gemstone.

How Does a CZ Compare to a Diamond?

• A chunk of cubic zirconia is heavier than a diamond of the same size, but not as hard. CZ is rated at 8.5 of the Mohs scale, versus diamond (the hardest substance) at 10 and corundum (sapphire and ruby) at 9.
• When you shop for CZ jewelry, the store will probably list a carat weight, but may call it a 'diamond equivalent,' to help you understand how the (heavier) CZ would compare to a diamond of the same visual size.
• Cubic zirconia can be transformed into the same popular cuts and shapes that are used for diamonds and colored gemstones.
• A white CZ is truly colorless, with none of the inclusions found in an untreated diamond -- think of it as a little too perfect.
• Cubic zirconia produces more flashes of color (fire) than a diamond.
• Some of today's CZ is coated with a product that makes the stones more durable and lessons their fire -- the stones look more like true diamonds, although a jeweler will know they are not.
• Colorful versions of CZ are available, too, and have become popular in sync with the trend towards fancy color diamonds.

Are There Different Grades of Cubic Zirconia?

Cubic zirconia can be evaluated using the same qualities that diamonds and other gemstones are graded by: the Four Cs (color, clarity, cut and carat weight).

• The quality of CZ's manufacture does vary -- some types are less desirable than others, and clarity is one characteristic that may differ.
• A five-tiered system of A (lowest grade) to AAAAA (highest grade) is used to designate cubic zirconia qualities, but most retail jewelry stores (online or off) do not refer to the grades; they're often seen when purchasing wholesale cubic zirconia.
• Ask questions and read descriptions carefully before purchasing cubic zirconia jewelry from any source.

Is a Cubic Zirconia Suitable for an Engagement Ring?

A CZ is not as durable as a diamond, sapphire or ruby, and that means it is more likely to become scratched over time. But if you cannot budget a diamond or other very durable gem, an engagement ring set with a cubic zirconia could be a good alternative -- at least for the short term.

Cubic zirconia works nicely when set into necklaces, earrings, bracelets, rings and other jewelry that is not worn on a daily basis.

How Should I Clean Cubic Zirconia Jewelry?

Cubic zirconia itself can be cleaned in an ultrasonic jewelry cleaner, but consider the setting materials before you drop the jewelry into the tank and turn on the switch. Use a less intense method to clean CZ jewelry crafted from sterling silver or from plated metals -- dishwashing detergent and a very soft brush may be all it takes to remove film from the CZ and return its fire.

Store cubic zirconia jewelry by itself, or well separated from gemstones that are rated as harder or softer on the Mohs scale -- that type of storage is important for all jewelry to avoid scratches.

Is Cubic Zirconia the Same as Zircon?

• Zircon (6 - 6.5 on the Mohs scale) is a gemstone, zirconium silicate, and is not related to cubic zirconia. Heat treated brown zircon was often made colorless with heat and used as a diamond substitute before CZ became available.
• Zircon found in most jewelry has probably been treated with heat to improve or change its color, and some of the stones may revert to their original colors after they are exposed to light.
• Heat treatments make zircon less durable.
• You may see the term cubic zirconium, but that substance does not exist (our Chemistry site explains why).
• Our Geology site explains zircon and other minerals, including CZ.