anorthosite

noun

an·​or·​tho·​site ə-ˈnȯr-thə-ˌsīt 

: a granular plutonic igneous rock composed almost exclusively of a soda-lime feldspar (such as labradorite)

anorthositic

ə-ˌnȯr-thə-ˈsi-tik 

adjective

Examples of anorthosite in a Sentence

Recent Examples on the Web

The presence of anorthosite on the moon suggested that the entire orb was once a magma ocean, or completely molten. — Jackie Wattles, CNN Money, 6 Apr. 2026

Because of its high alumina content, anorthosite is used to produce fiberglass and as a sustainable, low-carbon source of aluminum. — Ariel Cohen, Forbes.com, 20 Feb. 2026

Greenland’s only fully operational mine as of May 2025 extracts anorthosite rock at a site called White Mountain, on the central west coast of the island. — IEEE Spectrum, 8 May 2025

The discovery of anorthosite — an ancient type of rock formed from cooling molten lava — in the lunar highlands suggested that, early in its history, the Moon had vast magma oceans. — Anna Nordseth, Discover Magazine, 29 Oct. 2024

Off Planet’s recipes combine several rocks, including anorthosite and basalt. — Matthew Hutson, The New Yorker, 24 Sep. 2024

Word History

Etymology

French anorthose "triclinic (of feldspar)" (from an- an- + Greek orthós "straight" + French -ose -ose entry 1) + -ite entry 1 — more at ortho-

First Known Use

1863, in the meaning defined above

Rhymes for anorthosite

• actinolite
• adipocyte
• amphibolite
• anthophyllite
• aragonite
• carbonatite
• cassiterite
• chalcopyrite
• cristobalite
• crocidolite
• diatomite
• dithionite