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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...
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found to lack long
range order. The
lamellar separation only
occurs in
plagioclases of a
certain composition;
those of
calcic labradorite (50–70% anorthite)...
- 90
molecular percent of the
anorthite endmember. The
composition of
plagioclases is
often expressed as a
molar percentage of An%, or (for a
specific quantity)...
- 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...
- and
plagioclase makes up more than 65% of the
total feldspar content.
Gabbroids are
distinguished from
dioritoids by an
anorthite (calcium
plagioclase) fraction...
- phaneritic,
intrusive igneous rock
characterized by its composition:
mostly plagioclase feldspar (90–100%), with a
minimal mafic component (0–10%). Pyroxene...
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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...
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contains amphibole,
especially hornblende and actinolite, as well as
plagioclase feldspar, but with
little or no quartz. It is
typically dark-colored...
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plagioclase phenocrysts, but 4%
olivine microphenocrysts,
might be
termed an
aphyric to sp****ly
plagioclase-olivine
phyric basalt,
where plagioclase...
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Albite is a
plagioclase feldspar mineral. It is the
sodium endmember of the
plagioclase solid solution series. It
represents a
plagioclase with less than...
