It means that the ring is silver, and the stones are cubic zirconium.
10k refers to the weight of the stone or stones. CZ is cubit zirchonia.
The stones are not diamonds, but Cubic Zirconium (synthetic man made stones).
it means that the gold is real, but the stones are not. (cubic zirconium)
That the stone is not a diamond, it is a Cubic Zirconium