Cubic zirconia or CZ is one of the most popular lab-grown gemstones developed and is commonly used as a diamond simulant.
It shines as bright as the natural diamond, and to the untrained eye, the two could be confused for each other.
Sometimes it’s known as cubic zirconium, which brings in more confusion because the sparkle of the stones notwithstanding, zirconium is a metal that is transformed into crystal form as tetragonal zircon gemstone, a chemical derivative of zirconium silicate.
However, the standard diamond simulant, cubic zirconium, is made of zirconium oxide, with a cubic structure rather than a tetragonal structure.
Is cubic zirconia a gemstone with its chemical properties and composition in mind?
Is cubic zirconia a gemstone?
A gemstone is defined as a precious or semi-precious stone cut or polished for use in jewelry. So, going by this definition, cubic zirconia, a non-precious synthetic stone, is not a gemstone but a crystal.
What is cubic zirconia?
The synthetic cubic zirconia was first made in the lab successfully in 1973. However, experiments started in the 1960s – initially, the materials that now make CZ were used by scientists searching for the ideal materials for their lasers.
On the other hand, the first natural cubic zirconia was discovered in 1937 as a rare inclusion in the zircon crystals. After the discovery, the clear, brilliant, and sparkly crystals were used in the mass production of jewelry.
Thanks to its rarity, the lab-made forms of CZ became the popular and the most preferred forms of CZ from the first successful discovery. The main driving factor that encouraged the many processes now used to create CZ was the high cost of actual diamonds.
While most people envied the brightly shining diamonds, very few could afford them, so having an alternative that looks just as good as the diamond but for much less led to the popularity of the CZ.
As mentioned above, this lab-grown gemstone is made of zirconium dioxide or ZrO2, unlike the lab-grown and natural diamonds made of 4 carbon crystals stacked on each other into a cubic crystalline form. Cubic zirconia also features a cubic crystalline form, so it is the perfect diamond simulant.
In addition to its sparkle, the other features of CZ that make it the perfect diamond simulant include the fact that CZ is quite hard – it is harder than most other diamond simulants like the moissanite.
CZ scores a hardness level ranging from 8 to 8.5 on the Mohs scale of hardness against diamonds rated 10 on the scale. So, CZ crystals are among the hardest substances on earth.
CZ also boasts a high dispersion degree, making it relatively affordable and popular. It is also colorless, and depending on the quality of the cut; it reflects light just as well as diamonds.
Its colorlessness means that it is easily doped (color-treated) with specific elements, resulting in CZ stones in a wide color array. On the downside, the high specific gravity of CZ means that it tends to show more abrasion than diamonds.
CZ also boasts a high refractive index. And ultimately, the only difference between diamonds and CZ is their optical density, chemical, and physical properties.
How is Cubic Zirconia Made?
CZ stuns as the perfectly affordable diamond simulant with the same high-quality cuts and clarity levels. Also, with all the colors you may want to try out, how exactly is this diamond simulant made?
Is it made in conditions that simulate the natural CZ creation process from the mineral called baddeleyite, the natural zirconium oxide form?
CZ is created under extremely high-temperature conditions and through very specific processes. There are three main processes involved – melt, growth, and the solution growth processes. These processes can also be described as extremely high-temperature – high-pressure growth processes.
Of these processes, the solution techniques are similar to the ones used for the flux processing methods for rubies, emeralds, sapphires, spinel, and alexandrite.
The hydrothermal solution method is commonly used to create synthetic beryls like the emeralds, morganites, aquamarines, and the morganite, which takes place in the large, high-pressure vessel autoclave.
There are also several other techniques involved that use the solid-liquid state reactions and the phase transformations used for lapis lazuli and jade.
And for the melting processes, CZ is commonly made using the skull melting processes because of its high melting point.
More specifically, the high melting point of CZ is why the skull-melting method is the one applicable method when making CZ. The creation of CZ is in three steps – melting, cutting, and quality control.
Melting takes place in a hollow, skull-shaped copper cup where water circulates the hollow walls, cooling the interior walls of the skull. This cup is then filled with powdered ingredients, and it is heated through radio frequency induction until the ingredients melt.
But with the cooled skull walls, the powdered ingredients in the walls don’t melt. Still, the molten material remains within the shell of the unmelted powder, which also means that the high-temperature and reactive melt remains contained within itself.
In the second step, the system cools, and the heat source is removed. The cooling encourages crystal formation through the nucleation process, encouraging the crystals to grow until the entire melt fully solidifies.
But the crystals don’t grow to random sizes, there is a system, and also, the size of the crystals will differ depending on the total number of nucleations used.
Like diamonds, the cut of the CZ is just as important, with the proportion of the crystals being just as critical. Generally, the perfect cut is one whose specifications allow the maximum light to be reflected through the crystals. This cut is also called the Brilliant cut.
3. For the perfect cut, cutting takes place in a number of steps – marking the stone with the cleavage planes, splitting the stone, or cleaving/ sawing, and then, programmed precision cutting machines are used to cut the stones to specific cut sizes, depths, and sizes.
4. This is followed by rounding up or bruting where the cleaved edges are rounded.
5. After bruting, there is the faceting of the stone using the cast iron cutting wheel. Polishing is done after.
6. Finally, the cut stone is cleaned thoroughly by boiling the cut stones in acid, ensuring the removal of all traces of the diamond powder, dirt, and oil. The stones are then inspected under the microscope lens, and they are all packaged in the foam package.
7. Lastly, there is quality control, where the 4Cs are used to determine which CZ stones fall into which grade.
Should you buy cubic zirconia even if it is not a gemstone?
If you are looking for affordable jewelry that sparkle but will not break the bank, then jewelry made of cubic zirconia crystals would be ideal.
Cubic zirconia is a stunning, high-quality crystal or non-precious stone that looks just as good as natural diamonds but is not as expensive.
But because it is not classified as a precious or a non-precious stone, it is not valuable. That said, the CZ crystal is worth your money.
Tiger is a fashion&jewelry lover. He is also a fashion jewelry manufacturer that help thousands of small business to grow and also do business with some big fashion jewelry brands. He is a truly metal expert and he will share some information you are looking for.