Cubic Zirconia, or Cubic Zirconium as it's also called. It is similar to a diamond with its brilliance and crystal clarity, but it is a synthesized(man-made) crystalline material that is colorless, flawless and hard. It looks so much like a diamond, so it is a mineral often used in place of a real diamond.
One of the advantages of having a CZ stone can be made in different colors to simulate the different colors of a diamond.
Another great advantage is that cubic zirconia truly looks like the real thing. Because of its diamond-like qualities, overall durability, and low cost, even the wealthiest people wear cubic zirconia stones because it's a great way to keep up with the trends.