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

Etymology

Origin of anorthosite

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

Example Sentences

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

The team behind the new findings found evidence of ferroan anorthosite in the south pole.

From BBC • Aug. 21, 2024

Tarduno and his team used innovative strategies and techniques to examine the strength of the magnetic field by studying magnetism locked in ancient feldspar and pyroxene crystals from the rock anorthosite.

From Science Daily • May 3, 2024

On the second of their three days exploring Descartes, Young picked up a four-pound chunk of bright white stone that turned out to be anorthosite, a remnant of the moon’s original crust.

From Washington Post • Apr. 21, 2022

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