anorthosite

[ an-awr-thuh-sahyt ]

Phonetic (Standard)IPA

noun

, Petrology.

a granular plutonic rock composed largely of labradorite or a more calcic feldspar.

anorthosite

/ ænˈɔːθəˌsaɪt /

a coarse-grained plutonic igneous rock consisting almost entirely of plagioclase feldspar

anorthosite

/ ăn-ôr′thə-sīt′ /

An igneous rock consisting almost entirely of plagioclase feldspar, especially the labradorite variety. Anorthosites have been identified among rock samples collected from the Moon.

1860–65; < French anorthose anorthoclase ( an- an- ¹ + Greek orthós straight) + -ite ¹

C19: from French anorthose (see an- , ortho- ) + -ite ¹

In Canada great portions of the eastern portion of the Dominion are formed of gabbros, norite, anorthosite and allied rock types.

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