Shafranovskite

shafranovskite

thermonatrite

nacaphite

natrophosphate

Images

Formula: Na₃K₂(Mn,Fe,Na)₄[Si₉(O,OH)₂₇](OH)₂.nH₂O
Phyllosilicate (sheet silicate), manganese-bearing mineral
Crystal System: Trigonal
Specific gravity: 2.76 to 2.78 measured, 2.83 calculated
Hardness: 2 to 3
Streak: Green to yellow
Colour: Dark green to olive-green; Alters to greenish yellow, then to ochre-yellow
Solubility: Decomposed by 10% hydrochloric acid, reacts with water at room temperature and gives an alkaline solution
Magnetism: Strongly electromagnetic
Common impurities: Ti,Al,Mg,Ca
Environments

Pegmatites

Shafranovskite is produced by late-stage crystallisation of alkalic nepheline syenite magmas in pegmatites in differentiated alkalic massifs. Associated minerals include thermonatrite, natrophosphate, nacaphite, olympite, sidorenkite, aegirine, villiaumite, phosinaite and rasvumite (HOM).

Localities

There are two co-type localities, Rasvumchorr Mt, Khibiny Massif, Murmansk Oblast, Russia and the Yubileinaya pegmatite, Karnasurt Mountain, Lovozersky District, Murmansk Oblast, Russia.
At the type localities shafranovskite occurs in the alkalic pegmatites as fine-grained aggregates up to 5 mm across. Associated minerals include thermonatrite, natrophosphate, nacaphite, olympite, sidorenkite, rasvumite, and other sulphides (AM 68.644).
Shafranovskite from Rasvumchorr Mt - Image

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