Cubic Zirconia, popularly called "CZ," is a manufactured gemstone that is similar to diamonds to the untrained eye. The material from which CZs are made is zirconium dioxide, which is forced under laboratory conditions to shift from its regular monoclinic crystals to a cubic form by the addition of a chemical stabilizer. The result is a gem that is denser than a diamond, but not as hard. It also has more fire than real diamond, meaning that its facets display more internal rainbow colors. A close look at a CZ with a 10X loupe can quickly show that, despite its beauty and sparkle, CZs are not real diamonds: CZs are internally flawless, while most real diamonds contain internal inclusions, the record of their natural formation process. Nonetheless, CZs are a great and inexpensive way to bring sparkle to your jewelry designs. The addition of chemicals adds pretty color to these stones, and they can do something that diamonds can't: They can be set in PMC and fired safely in a kiln. NOTE: The price will depend on the size that you select. Next to each size is shown the number of stones (pcs) in stock, but we can easily backorder more if you need them.