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Formula:K2NaAlF6
Fluoride, cryolite subgroup,
perovskite supergroup
Crystal System: Isometric
Specific gravity: 2.995
Hardness: 2½
Streak: White
Colour: Colourless
Environments
Elpasolite is an uncommon secondary mineral formed in
pegmatites.
Localities
At the Cetine mine, Italy, elpasolite occurs on vein quartz in a
hydrothermal
antimony deposit in silicified
limestone, associated with
hydrokenoralstonite,
rosenbergite, gypsum,
fluorite and quartz
(HOM).
At the type locality, St Peters Dome, Cheyenne Mining District, El Paso county, Colorado, USA, elpasolite occurs
very sparingly with cryolite, pachnolite,
thomsenolite, prosopite and
gearksutite in vein-like bodies of quartz
and microcline in granite. The
cryolite was the original deposit and the other minerals were derived by alteration
either directly from the cryolite or from other, earlier-formed,
secondary fluorides. The elpasolite forms aggregates to
0.5 mm lining solution cavities in massive pachnolite. A little powdery
gearksutite is present and formed later than the elpasolite
(AM 33.84-87).
In the Morefield pegmatite, Amelia, Virginia, USA, elpasolite occurs in masses with
cryolite, chiolite,
pachnolite, thomsenolite,
prosopite and
hydrokenoralstonite
(HOM, Dana).
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