Cubic zirconia (CZ) is the cubic crystalline form of zirconium dioxide (ZrO2). The synthesized material is hard, optically flawless and usually colorless, but may be made in a variety of different colors. It should not be confused with zircon, which is a zirconium silicate (ZrSiO4). It is sometimes erroneously called "cubic zirconium". Because of its low cost, durability, and close visual likeness to diamond, synthetic cubic zirconia has remained the most gemologically and economically important competitor for diamonds since commercial production began in 1976. Its main competitor as a synthetic gemstone is the more recently cultivated material, syntheticmoissanite.
Measuring the Quality of Cubic Zirconia
When you are looking to buy cubic zirconia, you should first look at the quality of the stone carefully. When assessing the quality of cubic zirconia, you can go by the same "4C" scale that is used to grade diamonds. The four Cs to consider when choosing a quality cubic zirconia are carat, clarity, color, and cut.
Carat Weight of Cubic Zirconia
A cubic zirconia with the same dimensions as a diamond is about 1.7 times heavier than the diamond. When the weight of cubic zirconia is given in carats, the number actually represents the carat weight of a true diamond of the same size. This is to standardize the scale so that the comparison between cubic zirconia and diamond is easy to make. Some cubic zirconia stones are measured by stone size rather than carat weight.
Cubic Zirconia Clarity
All cubic zirconia in jewelry is manufactured synthetically, since it is not a mineral that exists in a naturally abundant and pure form. Low-quality manufacturing processes causes stones to be cloudy or have visible imperfections. Colored cubic zirconia can have uneven colors or tones, so the clearest and most evenly colored stones are the most valuable.
Colored Cubic Zirconia
When synthesized by a quality manufacturer, cubic zirconia is usually clear. It is possible to introduce elements and oxides to color stones during manufacturing. The mostly highly valued cubic zirconia stones have even color and tone. Unlike colored diamonds, which are exceptionally rare, cubic zirconia is affordable and available in a variety of colors.
The Cut of Cubic Zirconia Stones
Cubic zirconia can be hand-cut or machine-cut. For the best looking and most sparkling cubic zirconia, facets are cut evenly and precisely. The standard cut for cubic zirconia is the brilliant cut, but the stones can also be cut in other styles such as the trillion, princess and radiant styles. Quality cubic zirconia is hand-cut, not machine-cut, since machine cutting can cause stones to be hazy, poorly polished or have poorly arranged facets.
The "A" System of Rating Cubic Zirconia
When buying cubic zirconia, assess the quality by weight (carat), clarity, color and cut. The quality of cubic zirconia can also be measured by a separate system with six categories. The six categories used to describe the quality of cubic zirconia are: AAAAA,highest quality, AAAA, AAA, AA, A and AB, the lowest quality. The highest quality stones are hard and clear, while the lowest quality stones are cloudy and soft. Most cubic zirconias sold today are rated as AAA quality stones. Jewelers can find customers higher quality AAAA and AAAAA stones, if desired.