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Formula: Na4Be2Sn(Si3O9)2.2H2O
Inosilicate (chain silicate), beryllium-bearing mineral
Crystal System: Monoclinic
Specific gravity: 2.9 measured, 2.92 calculated
Hardness: 5½
Streak: White
Colour: Colourless to pinkish, altering to milky white; colourless in transmitted light
Luminescence: Fluorescent blue-white under long wave UV
Environments
Metamorphic environments
Hydrothermal environments
Sørensenite occurs on the floor of miarolitic cavities in hydrothermal veins cutting coarse-grained
nepheline syenites (HOM). It was approved in 1965, but
to date (December 2022) it has been reported only from Greenland.
Localities
There are two co-type Localities, Kvanefjeld and Mount Nakkaalaaq, both in the Ilímaussaq complex, Kujalleq, Greenland. Here
sørensenite occurs in hydrothermal veins in naujaite. The main
associates are analcime, microcline,
sodalite, neptunite and
aegirine.
The Kvanefjeld specimens were found in small bodies of a coarse-grained melanocratic rock which intrude into the
naujaite, lujavrite and
the contact metamorphosed roof rocks of the Kvanefjeld area. The main constituents of this rock are
microcline, nepheline,
analcime and arfvedsonite.
White patches very rich in analcime are scattered through the coarse-grained rock.
They may form vein-like bodies that are often zoned with narrow contact zones composed of
microcline, arfvedsonite and
steenstrupine-(Ce). The central zones are composed of
analcime, sodalite and
natrolite with minor amounts of
pyrochlore, neptunite, blue
apatite, lueshite,
monazite, chkalovite and
beryllite.
Neptunite and the closely associated
pyrochlore and lueshite occur in
fine-grained streaks in the analcime matrix.
Neptunite furthermore occurs as small brown crystals in cavities in the
analcime rock. Blue apatite and
sphalerite are found in grains up to about a millimetre in size.
In several analcime veins sørensenite is the next most abundant
mineral. It occurs in welldeveloped crystals 0.05 mm to 10 cm in size. The smallest grains often occur in clusters enclosed
in the analcime matrix. The sørensenite encloses
analcime, neptunite, blue
apatite and possibly sphalerite.
Analcime, when enclosed in sørensenite, is found as well-formed crystals of
a much larger size than in the surrounding rock, attaining a diameter of up to 1 cm. Patches of earthy white
beryllite are scattered through the vein. The
beryllite may enclose or fill the spaces in between sørensenite crystals
and may also be associated with large grains of chkalovite
(https://www.mindat.org/click.php?enc=aHR0cHM6Ly9ycnVmZi5pbmZvL3VwbG9hZHMvQ29udHJpYnV0aW9uX3RvX3RoZV9taW5lcmFsb2d5X29mX0lsJUMzJUFEbWF1c3NhcSxfTm8uXzEucGRm).
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