About Cubic Zirconia, History of Cubic Zirconia, Caring, Cubic Zirconia versus Diamond

Cubic zirconia (or CZ) is the cubic crystalline form of zirconium dioxide (ZrO₂).

The synthesized material is hard, optically flawless and usually colorless, 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 1976. It is sometimes marketed under the brand name "Diamonique". Its main competition as a synthetic gemstone is the more recently cultivated material, synthetic moissanite.

Cubic zirconia is relatively hard, at about 8 on the Mohs scale— slightly harder than most semi-precious natural gems. Its refractive index is high at 2.15–2.18 (B-G interval, compared to 2.42 for diamonds) and its luster is subadamantine. Its dispersion is very high at 0.058–0.066, exceeding that of diamond (0.044). Cubic zirconia has no cleavage and exhibits a conchoidal fracture. Because of its high hardness, it is generally considered brittle.

Cubic Zirconia jewelry ( also known as CZ jewelry) provides an extraordinary alternative to diamond jewelry. CZs tend to have slightly less brilliance (sparkle) than diamond, while having more fire (flashness of rainbow colors). The overall effect is so similar to diamond that trained gemologists often require special equipment to tell them apart. Undoubtedly the best diamond imitation subtitute available today, Cubic Zirconia has been established as an affordable diamond replacement as well as an important fashion piece. Cubic Zirconia is well known as a subtitute for diamond, due to its high hardness and great fire. But in recent years, it has established itself as gorgeous gem in its own right. CZ is a beautiful synthetic gemstone that is durable and inexpensive and now even comes in any color of the rainbow, making it even more desirable.

Cubic Zirconia (CZ) History

Cubic Zirconia was discovered in its natural state in 1937 by two German mineralogists, von Stackelberg and Chudoba. It was in a highly metamict zircon given to them by B.W. Anderson. The zircon contained tiny crystals that were determined to be the cubic form of zirconium oxide by x-ray diffraction. The two mineralogists thought so little of their discovery that they did not even give it a name; which is why it is still known by its scientific name, cubic zirconia. It wasn't until the 1970's, however, that Soviet scientists learned how to grow the crystals in the laboratory. In 1977, it was first marketed under the trade name "Djevalite." But CZ really took off in the 1980's when Swarovski & Co., a world-renowned Australian producer of leaded crystal, began producing cubic zirconia for mass consumption.

Caring for CZ

Cubic zirconia can be cleaned with any conventional jewelry cleaner or detergent. With such a high hardness and durability, you can use a brush to clean off dirt or oil also. Ultra sonic jewelry cleaners may also be used on CZ and will not damage the stone. However, when using soaps or detergents to clean CZ, one should wipe the jewelry dry thoroughly to avoid residue from the soap leaving a film that will dull the brilliance of the stone. Cubic Zirconia should be cleaned frequently to remove oils from skin that also dull the brilliance of the gem.

Cubic zirconia versus diamond

There are a few key features of cubic zirconia (CZ) which distinguish it from diamond, some observable only under the microscope or loupe, for example:

Dispersion: With a dispersive power greater than diamond (0.060 vs. 0.044) the more prismatic fire of cubic zirconia can be seen by even an untrained eye.
Hardness: Cubic zirconia has a rating of approximately 8 on Mohs hardness scale vs. a rating of 10 for diamonds.
Specific gravity: a cubic zirconia will weigh about 1.7 times more than a diamond of the same size.
Flaws: Contemporary production of cubic zirconia is virtually flawless, whereas most diamonds have some sort of defect, be it a feather, included crystal, or perhaps a remnant of an original crystal face (e.g. trigons).
Refractive index: Cubic zirconia has a refractive index of 2.176, compared to a diamond's 2.417.
Cut: Some cubic zirconia gemstones are cut with facet shapes which differ from those typically used for diamonds. This difference would be visible under close inspection with a loupe.
Color (or more precisely, the lack thereof): Only the rarest of diamonds are truly colorless, most having a tinge of yellow or brown to some extent. By comparison, cubic zirconia can be made in most cases entirely colorless: equivalent to a perfect "D" on diamond's color grading scale.
Thermal conductivity: Cubic zirconias are thermal insulators while diamonds are among the most efficient thermal conductors, exceeding copper. This makes telling the difference between diamond and cubic zirconia quite easy for those with the right instruments.