Girvasite
Girvasite is an IMA-recognized mineral species in the phosphate class, with the chemical formula NaCa₂Mg₃(PO₄)₃(CO₃)(H₂O)₆.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 3.5; specific gravity 2.46; White streak; Vitreous, silky in aggregates luster; optically biaxial.
IMA symbol Gvs, IMA status: approved, named in 1988.
A low-temperature hydrothermal mineral filling solution cavities in dolomite carbonatite in a differentiated alkaline massif.
It is found associated with Bobierrite, pyrite, dolomite.
The name refers to Lake Girvas, northwest of the Kovdor massif, Kola Peninsula, Russia.
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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