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Formula: (Na,Fe)2Ba2Sr2Ti2(SiO3)8(O,OH)2.H2O
Cyclosilicate (ring silicate), joaquinite group, monoclinic
paramorph of orthorhombic
strontio-orthojoaquinite,
barium-bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.68 calculated
Hardness: 5½
Colour: Green, yellow-green, yellow-brown
Common impurities: Li
Environments
Metamorphic environments
Hydrothermal environments
Strontiojoaquinite occurs associated with joaquinite-(Ce),
neptunite, natrolite,
albite, actinolite,
crossite, benitoite and
analcime
(HOM).
Localities
The type locality, Mina Numero Uno, Picacho Peak, San Benito county, California, USA, is in a large lens of metamorphosed
basalt, included as a tectonic block within a
serpentine body. The basaltic
block has been subjected not only to high pressure metamorphism, but also to considerable compositional modification by
fluids during the emplacement of the peridotite and
serpentinisation. The metamorphosed
basalt
is composed of a fine-grained intergrowth of albite,
crossite and aegirine. The rock mass
was fractured during the emplacement, forming cavities that are lined with recrystallised
albite and crossite; the cavities also
contain irregular concentrations of small crystals of benitoite, about 5 mm in
size, and neptunite, and even rarer, smaller crystals, about 1 mm in size, of
strontiojoaquinite.
Strontiojoaquinite was also found at a locality two miles southwest of San Benito Mountain. At this occurrence it
is associated with abundant albite and
actinolite and sparse benitoite (up
to 10 mm across), neptunite, analcime
and natrolite in veins cutting a tectonic block of metamorphosed
graywacke.
The host rock is composed of a granular assemblage of albite,
actinolite and titanite with the
relict sandstone texture weakly discernible
(AM 67.809-816).
Type material crystals of strontiojoaquinite were zoned with a
joaquinite core
(Mindat).
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