anorthosite

American  

[an-awr-thuh-sahyt] / ænˈɔr θəˌsaɪt /

noun

Petrology.

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

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anorthosite British  

/ ænˈɔːθəˌsaɪt /

noun

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

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anorthosite Scientific  

/ ăn-ôr′thə-sīt′ /

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

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Other Word Forms

• anorthositic
  adjective

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Etymology

Origin of anorthosite

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

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Example Sentences

See Examples For:

anorthosite

By examining these terrestrial rocks, scientists can investigate geological processes associated with the formation and evolution of anorthosite, helping them interpret the much older material found on the Moon.

From Science Daily ● Oct. 11, 2026

The anorthosite produced by this process remains a major component of the bright lunar highlands visible today.

From Science Daily ● Oct. 11, 2026

There are currently only two operational mines on the island -- one gold mine in the south, and one for anorthosite, a rock containing titanium, on the west coast.

From Barron's ● Feb. 14, 2026

Scientists think that when the Moon formed 4.5 billion years ago, it began to cool and a lighter mineral called ferroan anorthosite floated to the surface.

From BBC ● Aug. 21, 2024

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

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" by Various

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