Zirconium Silicates

Zirconium Silicates

 

a group of rare minerals, the basic structural elements of which are complex silicon-zirconium radicals of the following type: [Zr(Si3O9)]2– (the catapleiite sub group), [Zr(Si4O11)]2– (the vlasovite subgroup), [Zr(Si6O15)]2–(elpidite), {Zr [Si6O12(OH)6]}2– (lovozerite), and {Zr3 [Si3O9] · [Si9O24(OH)3]}9– (eudialyte). Na+, K+, Ca2+, Cr2+, Ba2+, and IR3+ serve as the cations in zirconium silicates. There are about 30 known zirconium silicates, for which framework and ring crystal structures are characteristic. The hardness of these minerals on Mohs’ scale is 4–5, and the densities range from 2,600 to 3,200 kg/m3. Zirconium silicates crystallize from highly alkaline melts and solutions. They are characteristic of nepheline syenites, syenite-pegmatites, and alkaline metasomatic zones, where they are associated with nepheline, natrolite, microcline, albite, aegirine (or aegirite), and other minerals.

References in periodicals archive ?
Zirconium silicates such as Zircopax Plus, Superpax, Opax, or Ultrox are frequently used in producing opacity in the glazes.