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Plagioclase (/ˈplædʒ(i)əˌkleɪs, ˈpleɪdʒ-, -ˌkleɪz/ PLAJ-(ee)-ə-klayss, PLAYJ-, -klayz) is a
series of
tectosilicate (framework silicate)
minerals within...
- pot****ium, or barium. The most
common members of the
feldspar group are the
plagioclase (sodium-calcium)
feldspars and the
alkali (pot****ium-sodium) feldspars...
- phaneritic,
intrusive igneous rock
characterized by its composition:
mostly plagioclase feldspar (90–100%), with a
minimal mafic component (0–10%). Pyroxene...
-
effect (schiller).
Labradorite is an
intermediate to
calcic member of the
plagioclase series. It has an
anorthite percentage (%An) of
between 50 and 70. The...
-
intrusive igneous rock
composed mostly of quartz,
alkali feldspar, and
plagioclase. It
forms from
magma with a high
content of
silica and
alkali metal oxides...
- and
plagioclase makes up more than 65% of the
total feldspar content.
Gabbroids are
distinguished from
dioritoids by an
anorthite (calcium
plagioclase) fraction...
-
sodic plagioclase (An70–85),
norites (
plagioclase-orthopyroxene), and
gabbronorites (
plagioclase-clinopyroxene-orthopyroxene) with
similar plagioclase compositions...
-
percentages of
quartz (crystalline
silica (SiO2)),
alkali feldspar,
plagioclase, and
feldspathoid (QAPF) are
particularly important. An
aphanitic (fine-grained)...
- is
enriched in
alkali metal oxides.
Monzonite is
composed mostly of
plagioclase and
alkali feldspar.
Syenodiorite is an
obsolescent term for monzonite...
-
Anorthite (an = not,
ortho = straight) is the
calcium endmember of the
plagioclase feldspar mineral series. The
chemical formula of pure
anorthite is CaAl2Si2O8...
