Cubic zirconia is the most used and most affordable imitation diamond. It is a completely synthetic stone, not occurring in nature. It is incorrectly called cubic zirconia.
Zirconium as such, of course, occurs in nature but has not a cubic but a square system and is chemically completely different from cubic zirconia.
Beautiful, olive green
Beautiful glittering facet cut, ideal wherever you need a little shine for a few crowns :-) made of suitable material