Since the introduction of the artificial Cubic Zirconia there has been some confusion between it and the Natural Zircon. However the mineral compositions of these two stones are quite different, with the Natural Zircon being composed of the mineral zirconium silicate and the artificial Cubic Zirconia being made from zirconium oxide.
Prior to the development of Cubic Ziconia, the natural gemstone, Zircon was an acceptable choice as a more cost effective alternative to the diamond – particularly because it has a refractive index higher than a diamond. Natural Zircon has many similarities to diamonds because of their luster and firey reflective ability. In their colorless forms they can easily be mistaken for diamonds. Natural gem quality Zircons are usually brown, although they can be found in many other colors, including yellow, orange, red, pink and green
Zircons can contain other elements such as hafnium, yttrium and uranium. This means that the gemstones can be mildly radioactive and as a result some of their crystalline structure may have broken down due to radioactive decay. Since natural zircons are commonly heat treated to improve their color, the heating process can also restore their crystalline structure.
Because of their radioactive element, the Zircon has played an important role in radiometric dating and shown that the stones were transported to the earth’s surface through basalt eruptions between 29 to 24 million years ago. This makes them the oldest known mineral to be dated so far.
Although Zircons are millions of years old, they were only discovered as recently as 1789, when Martin Klaproth, an apothecary, later to become a professor of chemistry, discovered both Uranium and Zirconium in the same year.
Currently, the major use for Zircons is industrial. Australia leads the world for mining Zircons although mines are also found in the United States and South Africa as well. Industrial grade zircon is used for a wide range of purposes including abrasives and insulators.
Whilst the Zircon does not manifest a hardness as much as the diamond (measuring at around 6.5-7.5 for a Zircon and 10 for a diamond) they are still reasonably hard stones and in their gem stone form make highly attractive, cost effective rings and other jewelry.