-
Perthite or
perthitic texture is used to
describe an
intergrowth of two feldspars: a host
grain of pot****ium-rich
alkali feldspar (near K-feldspar, KAlSi3O8...
-
Sanidine is
stable at the
highest temperatures, and
microcline at the lowest.
Perthite is a
typical texture in
alkali feldspar, due to
exsolution of contrasting...
- with pot****ium. The
resulting intergrowth of the two
feldspars is
called perthite. The higher-temperature
polymorph of KAlSi3O8 is sanidine.
Sanidine is...
-
charnockite series,
consisting essentially of quartz,
antiperthite (or
perthite),
orthopyroxene (usually hypersthene) and magnetite, and is equivalent...
-
composition alkali feldspars are
allowed to cool slowly,
exsolution occurs and a
perthite structure results.
Anorthoclase occurs in high
temperature sodium rich...
-
Pahangite (also "Pahangese")
Patna →
Patnaites Penang →
Penangite Perth →
Perthites (also "Perthian" and "Perthling")
Pullman →
Pullmanites Putney → Putneyites...
-
commonly represented by
orthoclase and the
exsolved lamellar albite, form
perthite. In some
rocks the
potash feldspar, in
others the soda
feldspar predominates...
- feldspars. The
feldspar has
partly unmixed on the micro-scale to form a
perthite, and the
presence of the
alternating alkali feldspar and
plagioclase layers...
-
intrusive rock,
which consists essentially of alkali-feldspar (orthoclase,
perthite, anorthoclase, and albite). Some
samples may
contain a
small amount of...
- "Dalmatian jasper" – not a
jasper at all but a form of the
igneous rock
perthite. The
black spots are
composed of the rare
amphibole arfvedsonite (and not...
