anorthite

American  

[an-awr-thahyt] / ænˈɔr θaɪt /

noun

Mineralogy.

1. a white or gray feldspar mineral, CaAl 2 Si 2 O 8 , calcic plagioclase.

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anorthite British  

/ ænˈɔːθaɪt, ˌænɔːˈθɪtɪk /

noun

1. a white to greyish-white or reddish-white mineral of the feldspar group and plagioclase series, found chiefly in igneous rocks and more rarely in metamorphic rocks. It is used in the manufacture of glass and ceramics. Composition: calcium aluminium silicate. Formula: CaAl 2 Si 2 O 8 . Crystal structure: triclinic

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anorthite Scientific  

/ ăn-ôr′thīt /

1. A white to gray triclinic mineral of the plagioclase feldspar group. Anorthite is the plagioclase mineral that is richest in calcium and occurs in alkaline igneous rocks such as gabbro. Chemical formula: CaAl ₂ Si ₂ O ₈ .

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Other Word Forms

• anorthitic adjective

Etymology

Origin of anorthite

First recorded in 1825–35; an- ¹ + orth- + -ite ¹

Example Sentences

Practically all varieties of this mineral from anorthite to albite are known to occur in basalt, but by far the commonest species are bytownite and labradorite.

From Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 3 "Banks" to "Bassoon" by Various

The specific gravity of the felspars has been shown by G. Tschermak and V. Goldschmidt to vary according to their chemical composition, rising steadily from 2.57 in orthoclase to 2.75 in anorthite.

From Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 2 "Fairbanks, Erastus" to "Fens" by Various

In anorthite, for example, these elements are a : b : c = 0.6347 : 1 : 0.5501; α = 93� 13′, β = 115� 55′, γ = 91� 12′.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" by Various

Felspar is a generic term which embraces a number of species, such as orthoclase or potash-felspar, albite or soda-felspar, and anorthite or lime-felspar.

From Geology by Geikie, James

Albite, the sodium felspar, has 68.8 per cent of silica, and the species between this and anorthite are regarded as mixtures of albite and anorthite molecules.

From The New Gresham Encyclopedia Volume 4, Part 3: Estremoz to Felspar by Various