plagioclase feldspar

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Related to plagioclase feldspar: anorthite, alkali feldspar, mica

pla·gi·o·clase feldspar

 (plā′jē-ə-klās′, -klāz′, plăj′ē-)
Any of a series of triclinic feldspars that are a common constituent of rocks, consisting primarily of a mixture of sodium aluminum silicate, NaAlSi3O8, and calcium aluminum silicate, CaAl2Si2O8.

[Greek plagio-, plagio- + Greek klasis, breaking (from its oblique cleavage) (from klān, to break).]
References in periodicals archive ?
Dominance of plagioclase feldspar over alkali feldspar is interpreted as being the result of high volcanic input.
In the latest work, Fourier-transform infrared spectroscopy was used to analyze the water content in grains of plagioclase feldspar from lunar anorthosites, highland rocks composed of more than 90 percent plagioclase.
CHEMIN RESULTS REVEALED: NASA's Curiosity rover gets its first taste of Mars and finds minerals: plagioclase feldspar, pyroxene and olivine.
Photomicrographs of sandstone of the Loralai Formation: (a) showing highly quartzose nature of the sample, 10x10, XPL; (b) monocrystalline quartz grain (circled),10x10, XPL; (c) polycrystalline quartz grain (circled), 10x10, XPL; (d) perthite grain (arrow) in the centre, 10x25, XPL; (e) plagioclase feldspar (circled) surrounded by quartz and lithic fragments set in spary calcite cement, 10x40, XPL; (f) back- scattered SEM image showing quartz and authigenic euhedral albite, bar scale shows 20 um.
Just like the rocks on Earth, Moon's have lots of basalt and olivine, pyroxene, and mafic breccias, along with plagioclase feldspar, also known as anorthosite.
This explains the high ratio of plagioclase feldspar as well as the subordinate grains identified in Table 1.