The cold crucible method is a method for producing synthetic cubic zirconia crystals. The method was developed by scientists at the Lebedev Institute of Solid State Physics of the Russian Academy of Sciences and applied for a patent in 1976. Due to the good physical properties of synthetic cubic zirconia crystals, colorless synthetic cubic zirconia quickly and successfully replaced other diamond imitations and became a good substitute for natural diamonds. Synthetic cubic zirconia is easy to be doped and colored, and crystals with various bright colors can be obtained, so it is welcomed by gem traders and consumers.