andesine


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andesine

[′an·də‚zēn]
(mineralogy)
A plagioclase feldspar with a composition ranging from Ab70 An30 to Ab50 An50, where Ab = NaAlSi3O8 and An = CaAl2Si2O8; it is a primary constituent of intermediate igneous rocks, such as andesites.
References in periodicals archive ?
Other plagioclase grains have distinct cores of higher An content (of andesine composition), which are commonly seriticized (Fig.
Zoned plagioclase with average composition of andesine is the most abundant mineral, with less abundant interstitial K-feldspar and quartz.
Much of the core shows extensive alteration but microprobe analyses of fresh samples revealed that the plagioclase in both anorthositic and gabbroic rocks has a fairly uniform andesine composition.