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Formula: Na7(PO4)2F.19H2O
Hydrated phosphate containing halogen
Crystal System: Isometric
Specific gravity: 1.71 to 1.72 measured
Hardness: 2½
Streak: White
Colour: White
Luminescence: Fluorescent, weak orange in both short wave and long wave UV (Webmin)
Solubility: Partially decomposes to a white powder on exposure to air, dissolves in water (Mindat)
Environments
Plutonic igneous environments
Pegmatites
Localities
At the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Quebec, Canada,
natrophosphate occurs in sodalite xenoliths in an intrusive alkalic
gabbro-syenite complex.
Associated minerals include villiaumite,
ussingite, vuonnemite,
lovozerite, eudialyte,
steenstrupine, chkalovite,
lueshite, serandite,
griceite and kogarkoite
(HOM).
At the Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia, natrophosphate occurs in miarolitic cavities
in phonolite, associated with
villiaumite, aegirine,
albite and eudialyte
(HOM).
At the type locality, the Material'naya Adit, Yukspor Mt, Khibiny Massif, Murmansk Oblast, Russia, natrophosphate
occurs as monomineralic aggregates up to 5 X 3 cm, sometimes surrounded by a rim of
villiaumite, in the central cavernous zone of a
pegmatite in
ijolite-urtite. On
exposure it alters and becomes covered by a film of villiaumite and
secondary phosphates (AM 58.139). Associated minerals
include villiaumite, aegirine,
delhayelite, strontian
apatite, natrolite,
pectolite and albite
(HOM).
At Karnasurt and Alluaiv Mountains, Lovozersky District, Murmansk Oblast, Russia, natrophosphate is a rare mineral
in an ijolite-urtite
pegmatite in a differentiated alkaline massif. Associated
minerals include villiaumite,
nahpoite, dorfmanite,
kogarkoite,
sidorenkite, thermonatrite,
analcime and aegirine
(HOM).
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