anorthite

American  

[an-awr-thahyt] / ænˈɔr θaɪt /

noun

Mineralogy.

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

---

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

---

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 .

---

Other Word Forms

• anorthitic
  adjective

Etymology

Origin of anorthite

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

Example Sentences

See Examples For:

anorthite

Of their minerals felspar Is usually the most abundant, and is principally labradorite and bytownite, though anorthite occurs in some, while oligoclase and orthoclase have been found in others.

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

The name anorthite was given to the Vesuvian mineral by G. Rose in 1823, on account of its anorthic crystallization.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" 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

Gabbro, from Carlingford Hill, Ireland, consisting of anorthite, augite, a little olivine, and magnetite.

From Volcanoes: Past and Present by Hull, Edward

In chemical composition and in optical and other physical characters it is thus much nearer to the anorthite end of the series than to albite.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary" by Various