Cubic Zirconia (ZrO2), also known as CZ, continuously populates the jewelry market as one of the most prominent diamond alternatives, due to its high hardness and great fire. 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 is undoubtedly the best diamond simulate available today. Cubic Zirconia has successfully established itself as the high quality and affordable diamond substitute in today’s fashionable jewelry market. It is a beautiful substitute for those who cannot afford a real diamond or just simply prefer not to spend that much.
Cubic Zirconia (CZ) was discovered in 1937 by two German mineralogists. It wasn’t until the 1970’s, however, that Soviet scientists learned how to grow the crystals in the laboratory. CZ did not become popular until the 1980’s when Swarovski & Co. began making them in mass production. CZ is not a natural occurring chemical structure. CZ is made through a complicated process and mostly it is about 87.5% zirconium oxide and 12.5% yttrium oxide. Together the two chemicals create a beautiful, radiant crystal. It takes almost 5,000 degrees Fahrenheit to melt the two chemicals together and the most important process is cooling. The chemicals must be carefully cooled in order to create flawless crystals.
There are very few substances on earth harder than CZ. With a hardness rating of 8.5, CZ comes close to matching diamond’s perfect 10. CZ has a specific gravity between 5.65 and 5.95, and a density between 5.5 and 5.9. Its refractive index is between 2.088 and 2.176, which is very high. It has dispersion slightly greater than diamond, and this produces an abundance of color play. Mostly all CZ on the market also contains yttrium oxide that acts as a stabilizer. In colored CZ, other oxides are added to produce the colors. Since CZ is transparent, it is often faceted. It can be made in nearly any color and can be faceted into many cuts. The finest CZ’s are perfect in clarity. The finest CZ is cut to exacting tolerances, according to the proportions demanded in fine diamond cutting. Finely cut CZ’s will have a polished girdle and more fire.
To the untrained and naked eye, CZ looks identical to a good quality diamond, even gemologists cannot tell the difference unless various testing and examination is done. CZ has slightly less brilliance or sparkle than a diamond and more fire or flashes of color. One great difference between CZ and diamond is weight. CZ is about 75% heavier than diamond. As such, a CZ’s size is referred to in carats only as in comparison to diamonds. CZ is more accurately measured in millimeters, referring to the diameter. A 6.5mm CZ is equal in size to a one-carat diamond and actually weighs about 1.75 carats. CZ is also more brittle and softer than diamond. CZ is also flawless, whereas diamond usually contains impurities and inclusions.
One of the ways to tell the difference between a CZ and a real diamond is to look at the CZ under a 10x magnification. One can see that the facets do not point properly, and where facets intersect, it is not a straight line, but the intersection is more rounded than the diamond’s facets. Other ways to tell the difference are doing a specific gravity test on an un-mounted stone, marking ink on the top of the stone (the ink beads up on a CZ), when gem-printed a CZ photograph’s reflective and refractive patterns, and when measuring heat conductivity, a CZ registers red on the indicator (a diamond is green).
Avoid touching CZ stones; the natural oils on fingers can leave a film that dulls the brilliance. CZ can be cleaned with any conventional jewelry cleaner or detergent. However, other cleaners can be used, preferably those without ammonia. Natural skin oils, soap, and dirt cause a film that dulls the beauty and luster of the CZ, just as it dulls real diamonds. With such a high hardness and durability, a wearer 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. CZ should be cleaned frequently to remove oils from skin that also dull the brilliance of the gem.