Kapustinite
Kapustinite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₆ZrSi₆O₁₆(OH)₂.
It crystallizes in the trigonal crystal system (space group C2/m). It is a member of the Lovozerite-Zirsinalite–Lovozerite structural group.
Key properties: Mohs hardness 6; specific gravity 2.78; Pale lilac streak; Vitreous luster; optically biaxial.
IMA symbol Kpu, IMA status: approved, named in 2003.
Found in hyperagpaitic pegmatite in an alkaline massif.
It is found associated with Microcline, aegirine, kazakovite, ussingite, sodalite, analcime, natrosilite, villiaumite.
The mineral was named to honor mineralogist Yu. L. Kapustin (1933–2002), who extensively studied alkaline massifs.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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