what is cz
Technical aspects [edit]. Cubic zirconia is crystallographically isometric, an important attribute of a would-be diamond simulant. During synthesis zirconium oxide would naturally form monoclinic crystals, its stable form under normal atmospheric conditions.herefore the physical and optical properties of synthesized CZ vary, all values being ranges. It is a dense substance, with a specific gravity between 5.6 and 6.0 â at least 1.6 times that of diamond. Cubic zirconia is relatively hard, 8â8.5 on the Mohs scale â slightly harder than most semi-precious natural gems.