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Oligoclase is a rock-forming
mineral belonging to the
plagioclase feldspars. In
chemical composition and in its
crystallographic and
physical characters...
- Gotthard.[better source needed] A
solid solution of the
plagioclase feldspar oligoclase +/− the pot****ium
feldspar orthoclase also
produces moonstone specimens...
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silica and
related volcanics such as andesite.
Oligoclase is
common in
granite and monzonite. The name
oligoclase is
derived from the Gr**** [[[wikt:ὀλίγος|olígos]]]...
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Sunstone is a
microcline or
oligoclase feldspar,
which when
viewed from
certain directions exhibits a
spangled appearance. It has been
found in Southern...
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Osumilite Otavite Ottrelite Otwayite Varieties that are not
valid species:
Oligoclase (a
mixture of
albite and anorthite) Onyx (a
monochromatic banded variety...
-
follows (with
percent anorthite in parentheses):
albite (0 to 10) NaAlSi3O8
oligoclase (10 to 30) (Na,Ca)(Al,Si)AlSi2O8
andesine (30 to 50)
NaAlSi 3O 8 – CaAl...
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plagioclase is
typically intermediate to
sodic in composition,
andesine to
oligoclase.
Quartz is
present in
significant amounts.
Biotite and/or
hornblende constitute...
-
biotite (sp. gr. 3.1),
muscovite (sp. gr. 2.85),
quartz (sp. gr. 2.65),
oligoclase (sp. gr. 2.64), and
orthoclase (sp. gr. 2.56), the
crushed minerals float...
- K)AlSi3O8
Sanidine – KAlSi3O8
Plagioclase feldspars Albite – NaAlSi3O8
Oligoclase – (Na,Ca)(Si,Al)4O8 (Na:Ca 4:1)
Andesine – (Na,Ca)(Si,Al)4O8 (Na:Ca...
- (var.)
Rainbow (var.)
Orthoclase Unakite Plagioclase Albite Labradorite Oligoclase Sanidine Sunstone Oregon sunstone Rainbow lattice sunstone Fergusonite...
