What is Vlasovite?
Vlasovite is a rare sodium zirconium silicate from alkaline complexes, recognised by pale crystals and an unusual zirconium-bearing framework.
Mineralogy and structure
Reference formula: Na2ZrSi4O11. Vlasovite is monoclinic. COD 9009431 provides an exact structural reference, while natural crystals can show alteration and associated aegirine, nepheline or eudialyte. Vlasovite is classified with silicates and has monoclinic crystal symmetry. Typical hardness is 6–6.5 on the Mohs scale and specific gravity is approximately 3.2–3.4.
Colour, lustre and habit
Typical colours include white, colourless, pale yellow, grey, pinkish. The usual prismatic, acicular, granular habit and vitreous, pearly lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Vlasovite forms in or is associated with alkaline pegmatites, nepheline-syenite complexes and late-stage sodium-rich cavities. Important documented localities include the Kola Peninsula in Russia, Greenland, Canada, Norway and the United States.
Pale zirconium silicate from a rare-metal complex
Vlasovite appeals to collectors of unusual alkaline mineralogy: modest colour is offset by sharp form, zirconium chemistry and a host rock that records highly evolved magma.
Collecting and care
Protect from impact and acids; clean with mild water and retain the alkaline host-rock information.
