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Formula: (La,Ce,Ca)4(Fe2+,Mn)(Ti,Fe3+,Al)4[(Si2O7)O4]2
Sorosilicate (Si2O7 groups), chevkinite group,
lanthanum-,
cerium-, manganese- and
titanium- bearing mineral
Crystal System: Monoclinic
Specific gravity: 4.791 calculated
Hardness: 6
Streak: Brown
Colour: Black
Environments
Volcanic igneous environments
Pegmatites
Localities
At the type locality, In den Dellen quarries, Mendig, Mendig, Mayen-Koblenz District, Rhineland-Palatinate, Germany,
perrierite-(La) occurs as isolated prismatic crystals, up to 0.5 x 1 mm in size, in miarolitic cavities in
sanidine-bearing lava rock. Associated minerals include
sanidine, phlogopite,
pyrophanite, zirconolite,
jacobsite, magnetite,
fluorcalciopyrochlore and
zircon
(HOM, Mindat).
The Buer, Bjørkedalen, Porsgrunn, Vestfold og Telemark, Norway, deposit is the only one where both
chevkinite and perrierite occur together. The occurrences are of
two main types: one type is in pegmatites located in
basaltic rocks near the contact with
larvikite, and the other in
pegmatites in massive
larvikite.
Perrierite is common in syenite
pegmatites where
zircon and pyrochlore are also
abundant; it occurs in crystal aggregates with a loparite-(Ce) and
pyrophanite core, sometimes with inclusions of
apatite. The
pegmatite consists mainly of
microcline, biotite and
aegirine. Accessories include
zircon, pyrochlore,
leucophanite and
pyrophanite. The dike is in places heavily
zeolitised with analcime,
natrolite and thomsonite
(AM 63.499-505).
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