In this recent series of exploring the differences between natural diamonds and cubic zirconias (CZ), we have examined the toughness, hardness, dispersion, weight and colour of each of these stones. While we have identified glaring differences between the quality of the CZ when compared with the natural diamond, perhaps the most fascinating differences are in their simple creation.
The Creation of the Synthetic CZ
For generations, scientists have explored how to re-create the natural diamond in such a way that the synthetic could easily be substituted for the real thing. Simple class couldn’t come close to the brilliance of a natural diamond, but the cubic zirconia does a pretty good job of impersonation.
As the crystalline form of zirconium dioxide, the cubic zirconia is a synthesized material that is hard, optically flawless and usually colorless. Since 1976, this gem has been considered the most aggressive competitor against diamonds and is sometimes marketed under the brand name, “Diamonique.”
While nature creates the perfect environment for the creation of a beautiful diamond, man must take the reigns when it comes to the CZ. During the synthesis of the cubic zirconia, zirconium oxide will create monoclinic crystals in a stable environment. To create that environment, a stabilizer must be used when the zirconia is heated to an impressive 2750 degrees Celsius in order to control the growth of the crystals.
Once the zirconia melts, a thin shell is left behind that remains solid as it is cooled by the water in the copper fingers. In this process, the zirconia and the stabilizing oxide are added. To achieve the desired uniformity in the stone, the contents are kept molten for a number of hours. While it is a proven process, it is one that takes precision and focus to produce a gem perfect enough to pass as a diamond substitute. 
The Creation of a Brilliant Natural Diamond
The creation of a natural diamond requires two important elements: carbon and time. When these two elements are combined under high pressure and high temperatures, a diamond can eventually emerge. The majority of natural diamonds are formed under such conditions in the earth’s mantle.
It is estimated that it takes from 1 billion to 3.3 billion years to complete the creation of the natural diamond. When this process is complete, the diamond must be brought closer to the surface of the earth in order to be mined – an action that also relies on nature. Deep volcanic eruptions can bring a diamond closer to the surface or continental plates can collide to push diamonds and other minerals upward. 
Extreme geological conditions are necessary to form a natural diamond. The temperature must be greater than 800 degrees Celsius and the pressure must be 50,000 times atmospheric pressure. Such conditions on earth only exist at 150km to 200km below the surface.
In such conditions there exists cratons, deep keel-like roots of old stable continental crust. These cratons formed near the bottom of plates at the same time and location as the formation of diamonds. Among the cratons, diamonds will remain unless they are brought to the surface through natural processes. 
While we have discussed that the brilliance, toughness and pure value of the diamond surpasses the cubic zirconia every time, perhaps the most important element of consideration is the fact that the natural diamond is rare. CZ stones can be created time and again, while there is a finite number of natural diamonds available and the waiting list for the next round is beyond our comprehension.