Caring for your Cubic Zirconia
You should care for your Cubic Zirconia using warm, soapy water and a soft brush or using an ultrasonic jewelry cleaner. Although CZ is very hard, it is softer than diamonds and should be cared for as such. You should clean your Cubic Zirconia frequently to remove the oils from your skin that dulls the brilliance of the gem. If you properly care for you gems, they should continue to look beautiful forever.
History
Cubic Zirconia was originally discovered in its natural state in 1937 by two German mineralogists. The zirconia they discovered, contained tiny crystals that were determined to be the cubic form of zirconium oxide. The two mineralogists thought so little of their discovery that they didn't even give it a name; which is why it's still known by its scientific name - cubic zirconia. In the 1970's Soviet scientists learned how to grow the crystals in a laboratory. In 1977, it was first marketed under the trade name "Djevalite". But it took off in the 1980's when Swarovski began producing CZ for mass consumption. Since then it is manufactured by select companies throughout the world.
How Cubic Zirconia is Made
To produce CZ, baddeleyite (ZrO2 ) is heated to almost 5,000 degrees Fahrenheit. At this temperature the mineral becomes isometric (crystalization characterized by three equal axes at right angles). Since it is not stable in this form, a stabilizer is added. Exactly the right amount of stabilizer is added in order to retain the brilliancy of the product.
The melting of CZ requires such a high temperature that a special radio frequency crucible is needed to melt the zirconia powder. This crucible consists of a cup like arrangement made up of a circle of copper fingers which is water cooled by internal plumbing. As the zirconia powder melts, it leaves a thin shell that remains solid due to cooling by the water in the copper fingers. As this occurs the zirconia and the stabilizing oxide are added to fill the crucible to the desired level. The contents are kept molten for several hours to ensure uniformity. To produce colors, oxides of cerium, copper, titanium, iron, nickel, and many other elements are added.
Physical Properties
Cubic zirconia has a hardness of 8.5 on Moh's Scale of Hardness. Its specific gravity is between 5.65 and 5.95, its density is between 5.5 and 5.9. CZ's refractive index is between 2.088 and 2.176, which is very high. It has dispersion in the C-F area of the visible light spectrum of 0.060. Since CZ is transparent, it is often faceted to show its brilliance. It can be made in nearly any color and can be faceted into many different cuts. |
