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Formula: (K,Ba,Na)2(Ti,Nb)2(Si4O12)(OH,O)2.3H2O
Valence:
(K,Ba,Na)2(Ti4+,Nb5+)2Si4O12(OH,O)2.3H2O
Cyclosilicate (ring silicate), vuoriyarvite group,
labuntsovite supergroup,
barium-,
titanium- and
niobium- bearing
mineral
Crystal system: Monoclinic
Specific gravity: 2.88 measured, 2.97 calculated
Hardness: 5
Streak: White
Colour: Colourless
Common impurities: Ba,Na
Environments
Pegmatites
Hydrothermal environments
Tsepinite-K occurs in cavities formed by hydrothermal alteration of alkaline
pegmatites. Associated minerals include
labunstovite group minerals,
aegirine, manganoneptunite,
natrolite, chabazite-Ca,
yofortierite, nontronite and
kaolinite subgroup minerals. Tsepinite-K is pseudomorphous
after murmanite.
(HOM).
Localities
At the type locality, the Karnasurt Mountain, Lovozersky District, Murmansk Oblast, Russia, tsepinite-K occurs
in the alkaline pegmatite as short-prismatic colourless
crystals up to 0.4 mm length, and in pseudomorphs after
murmanite. Associated minerals include
aegirine, chabazite-Ca,
manganoneptunite and
natrolite
(Mindat).
Tsepinite-K from Karnasurt Mountain -
Image
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