Zirconium dioxide jewellery. Like diamond, cubic zirconia has a cubic crystal structure and a high index of refraction. Visually discerning a good quality cubic zirconia gem from a diamond is difficult, and most jewellers will have a thermal conductivity tester to identify cubic zirconia by its low thermal conductivity (diamond is a very good thermal conductor). This state of zirconia is commonly called "cubic zirconia", "CZ", or "zircon" by jewellers, but the last name is not chemically accurate. Zircon is actually the mineral name for naturally occurring zirconium silicate (ZrSiO). Zirconium dioxide Zirconium dioxide (), sometimes known as zirconia (not to be
Recycled diamond Recycled diamond A recycled diamond is a diamond, which had a prior use and has re-entered the diamond supply chain. Diamonds in recent times have become good candidates for recycling, due to a number of reasons including their hardness and the gemstone being a finite and valuable resource. Diamonds are the hardest known naturally occurring substance and rate a 10 on the Mohs scale of mineral hardness. It has been speculated that the value of the market could be as high as $1 trillion US dollars. Traditionally, diamonds are considered a valuable commodity and large quantities of rough diamonds have