Editing Cubic zirconia (section)

==Technical aspects==
Cubic zirconia is [[crystallography|crystallographically]] [[Cubic crystal system|isometric]], an important attribute of a would-be [[diamond simulant]]. During synthesis zirconium oxide naturally forms [[monoclinic]] [[crystal]]s, which are stable under normal atmospheric conditions. A stabilizer is required for cubic crystals (taking on the [[fluorite structure]]) to form, and remain stable at ordinary temperatures; typically this is either [[yttrium]] or [[calcium]] oxide, the amount of stabilizer used depending on the many recipes of individual manufacturers. Therefore, the physical and optical properties of synthesized CZ vary, all values being ranges.

It is a dense substance, with a [[density]] between 5.6 and 6.0&nbsp;g/cm<sup>3</sup>—about 1.65 times that of diamond. Cubic zirconia is relatively hard, 8–8.5 on the [[Mohs scale of mineral hardness|Mohs scale]]—slightly harder than most semi-precious natural [[gemstone|gems]].<ref name="Mohs' Hardness of Abrasives">{{cite web| url = http://www.reade.com/resources/reference-charts-particle-property-briefings/851-mohs-hardness-of-abrasives| title = Mohs' Hardness of Abrasives| access-date = 6 June 2009| url-status = dead| archive-url = https://web.archive.org/web/20091017120910/http://www.reade.com/resources/reference-charts-particle-property-briefings/851-mohs-hardness-of-abrasives| archive-date = 17 October 2009| df = dmy-all}}</ref> Its [[refractive index]] is high at 2.15–2.18 (compared to 2.42 for diamonds) and its [[Lustre (mineralogy)|luster]] is [[Lustre (mineralogy)#Adamantine lustre|Adamantine lustre]]. Its [[dispersion (optics)|dispersion]] is very high at 0.058–0.066, exceeding that of diamond (0.044). Cubic zirconia has no [[cleavage (crystal)|cleavage]] and exhibits a [[conchoidal fracture]]. Because of its high hardness, it is generally considered  [[Brittleness|brittle]].

Under shortwave [[UV]] cubic zirconia typically [[fluorescence|fluoresces]] a yellow, greenish yellow or "beige". Under longwave UV the effect is greatly diminished, with a whitish glow sometimes being seen. Colored stones may show a strong, complex [[rare earth element|rare earth]] [[absorption spectrum]].