When cubic zirconia first appeared in 1978, it quickly became popular due to its extraordinary similarity to diamonds. Russian Formula cubic zirconia – the premium grade of five general types available commercially – was selling in the late 70s for prices that would now be considered exorbitant. Over time it has become much more affordable (especially given inflation), and CZ has become even more of a hit.
In fact, gemologist Robert James, FGA, GG, notes that cubic zirconia holds a prominent position in the jewelry community: “There is no synthetic gemstone on the market that has had a greater impact on the jewelry industry than cubic zirconia.”
It would seem obvious that the stone was created by design – that scientists had a breakthrough in the search for a viable, low-cost diamond alternative. However, James and other professionals note that, as a jewel, cubic zirconia is a happy accident. Its invention arose from research and development in other areas of technology.
A beautifully designed cubic zirconia ring is the epitome of elegance and glamour, so it makes sense that the stone’s birth sounds like something out of a James Bond movie.
Cubic zirconia: a replacement for rubies
Oddly enough, the first cubic zirconia was not created to resemble and substitute diamonds. Instead, scientists were attempting to generate a synthetic version of the ruby.
In the 1970s, rubies were a necessary component of lasers. As the Russians became more interested in lasers, they grew frustrated that genuine rubies were not readily available and decided to try creating their own. In their attempts to produce a compound that shared similar characteristics to the ruby, they invented cubic zirconia.
Although CZ is quite different from the ruby in terms of its immediate appearance and gemological attributes, its incredible clarity meant that it filled the need of the laser program. The scientists also noticed how closely the material shared the appearance of a diamond, so it started being produced for jewelry as well. Needless to say, soon the initial use in lasers was overshadowed by its strong performance in the jewelry world.
Cubic zirconia’s gemology
The structure of the crystals within diamonds is cubic. For that reason, any synthetic material attempting to resemble diamonds will ideally have a cubic makeup so that the mimicry is as keen as possible (unlike synthetic moissanite, which is not standardly made in a cubic formation).
Cubic zirconia is a sort of scientific miracle. First of all, zirconium is a metal. Also, when crystallized as zirconium silicate (forming a different, less popular type of stone known as zircon), its natural structure is tetragonal rather than cubic. On the other hand, when oxygen is used in place of silicon for the chemical reaction, zirconium (as zirconium oxide) crystallizes in the cubic structure that allows it to more closely resemble a diamond.
The crystallization that takes place in the creation of cubic zirconia is entirely “man-made.” Zirconium occurs in the silicate form in nature, where it has a tetragonal structure just as it does under laboratory conditions. However, either of two elements – yttrium or calcium – can be added in small quantities prior to crystallization, which enhances the stability of the metal. In turn, zirconium creates cubic crystals with available oxygen.
The issue of heat: another technological connection
Creating zirconium oxide in the desired crystal structure – cubic – was only one aspect of its invention. Scientists originally faced what seemed to be an insurmountable problem: it could not be held in a container (called a crucible). Why? Its melting point is almost unbelievably high, an incredible 4919°F.
When cubic zirconia was first created, scientists needed something in which to store the compound when it was created. However, nothing existed that could serve the purpose. For example, platinum has a melting point of 3215°F. No metals were capable of maintaining their solid form at the high level required for the creation of CZ.
The high melting point presented a major setback for the Russian scientists. However, most of us now have a household appliance that uses the force necessary to melt cubic zirconia within a container: the microwave.
Many people who use microwaves regularly do not realize that they heat starting at the center. The surface and edges of a dish prepared in a microwave can remain relatively cold while the interior becomes extremely hot.
In the case of cubic zirconia, a process called skull melting is achieved – essentially, the material becomes soft on the inside and hard on the outside (like the skull protecting the brain). Skull melting provides an environment in which cubic crystallization can occur by allowing the substance to serve as a crucible for itself.
Finding high-quality cubic zirconia
Although the basic chemical composition of cubic zirconia is formulaic, differences in how it is generated have a profound impact on its effectiveness at diamond simulation. To this day, Russian Formula remains the gold standard. Jewelry made from cubic zirconia should also always have a personal touch, as provided by the hands-on work of our master artisans.
By Kent Roberts