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Formula: Na4BaTi2B2Si10O30
Phyllosilicate (sheet silicate), barium-,
titanium- and boron- bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.04 to 3.09 measured, 3.103 calculated
Hardness: 6 to 6½
Streak: White
Colour: Colourless, lemon yellow, brown, pale blue
Solubility: Insoluble in acids
Common impurities: Al,Fe,Nb,Mn,Mg,Ca,Sr,K
Environments:
Localities
At Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Quebec, Canada, leucosphenite occurs in pegmatite in
syenite associated with albite,
aegirine, narsarsukite,
molybdenite, calcite and
fluorite
(HOM, AM 57.1801-1822).
The type locality is the Narssârssuk pegmatite, Narsaarsuk Plateau, Igaliku, Kujalleq, Greenland, Denmark, leucosphenite occurs
in pegmatite in syenite associated with
elpidite, aegirine,
epididymite, albite and
polylithionite
(HOM, AM 57.1801-1822).
At the Alaiski massif, Turkestan, Kazakhstan, leucosphenite is found with
reedmergnerite,
eudialyte,
stillwellite-(Ce),
pyrochlore, calcite and
galena as accessories in pegmatites composed mainly of
microcline, aegirine,
albite and quartz
(AM 57.1801-1822).
At the Karnasurt mountain, Lovozersky district, Murmansk Oblast, Russia, leucosphenite occurs with
neptunite and eudialyte
(FM 75755).
At the Inaglina massif, Yakutia, Russia, leucosphenite occurs in pegmatite in
syenite
in aegirine - feldspar veins associated with
arfvedsonite, eudialyte,
neptunite, lamprophyllite and
lorenzenite
(HOM, AM 57.1801-1822).
At the Green River Formation, Utah and Wyoming, USA, leucosphenite occurs with shortite
and analcime (Dana) as
an authigenic mineral in shale (HOM).
Nepheline has not been found here, although hydrous sodium aluminosilicates such as
analcime are abuirdant and widespread
(AM 57.1801-1822).
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