Primary Test: Magnification should be all you need to identify cubic zirconia. The “read through” of the stone will separate it from diamond, and the complete lack of any body color will separate it from synthetic moissanite. You should also know that the CZ testers on the market are not 100% reliable. We have seen many over the counter buys from jewelers who relied on a tester, only to find out later that the tester gave a wrong reaction. So practice identification of CZ using 10x. It could save you from a very expensive mistake. Also be aware that CZ is being used to create some pretty strange gems including color change and composite gems as seen above that are unlike anything in nature.
Secondary Tests: The refractive index of cubic zirconia is significantly lower than diamond, which can be a diagnostic test if one has a Jemeter Digital 90 reflectance meter. This gemological tool will give a RI reading above the 1.81 range of a regular refractometer and provide a separation of diamond and cubic zirconia. The 2.17 RI of CZ is significantly less than the 2.41 of diamond.
Repair and Setting: Not recommended for heating, but cleaning in ultrasonic should not be a problem. Should not be confused with diamond properties for heating as the reaction of CZ to a torch will be far more delicate than diamond.