Cubic Zirconia (CZ) is a man made material and comes from all over the world.
There are several methods of making it and there are some variances in both refractive indexes (R.I. 2.14-2.20) and hardness (8-9).
It is available in almost any color you can imagine and there are even some color change (fluorescent/incandescent, i.e. blue/red for example) varieties.
CZ is readily available and very inexpensive, usually pennies per carat. The corollary is that it is not really worth anything when cut.
Note: CZ is hard on laps and can cause undue wear. I do not recommend it for the brand new cutter, it can be problematic to polish and is best cut when a person has some experience.
Some people, especially if they want to cut large clean stones enjoy cutting it and because of it’s high R.I., it can be quite pretty. CZ needs to be polished with diamonds, the laps used can be ceramic, tin, copper, and ultra laps.