Natural gems stones are formed at high temperature and pressure at depths of 140 to 190 kilometers the Earth’s mantle.  Cubic zirconia crystals are made by melting powdered zirconium and zirconium dioxide together and heating them up to 4,982ºF. Cubic zirconia is a mineral that is used as a diamond stimulant and is widely synthesized. Cubic zirconia is not a diamond however it looks like a diamond, and has many diamond-like qualities. Cubic zirconia (also known as CZ) is similar to a diamond with its brilliance and crystal clarity, but it is a synthesized (man-made) crystalline material that is colorless, hard, and flawless.