CZ (Cubic Zirconia) stones are lab-grown gemstones, designed to fit in our claw settings.
Cubic zirconia (CZ) is the cubic crystalline form of zirconium dioxide (ZrO2). The synthesized material is hard and usually colorless, but may be made in a variety of different colors. It should not be confused with zircon, which is a zirconium silicate (ZrSiO4). It is sometimes erroneously called cubic zirconium. (Wikipedia)
CZ’s are an inexpensive diamond alternative.