biotite

American  

[bahy-uh-tahyt] / ˈbaɪ əˌtaɪt /

noun

1. a very common mineral of the mica group, occurring in black, dark-brown, or dark-green sheets and flakes: an important constituent of igneous and metamorphic rocks.

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biotite British  

/ ˈbaɪəˌtaɪt /

noun

1. a black or dark green mineral of the mica group, found in igneous and metamorphic rocks. Composition: hydrous magnesium iron potassium aluminium silicate. Formula: K(Mg,Fe) 3 (Al,Fe)Si 3 O 10 (OH) 2 . Crystal structure: monoclinic

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biotite Scientific  

/ bī′ə-tīt′ /

1. A dark-brown or dark-green to black mica. Biotite is monoclinic and is found in igneous, metamorphic, and sedimentary rocks. Chemical formula: K(Mg,Fe) ₃ (Al,Fe)Si ₃ O ₁₀ (OH) ₂ .

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Other Word Forms

• biotitic
  adjective

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Etymology

Origin of biotite

1860–65; named after J. B. Biot (1774–1862), French mineralogist and mathematician; see -ite ¹

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Example Sentences

See Examples For:

biotite

Geochemical fingerprinting of the widespread Toba tephra using biotite compositions.

From Nature ● Mar. 11, 2018

Chlorite, muscovite, biotite, garnet, and staurolite are index minerals representing a respective sequence of low-to-high grade rock.

From Textbooks ● Jan. 1, 2017

In some cases, hornfels has visible crystals of minerals like biotite or andalusite.

From Textbooks ● Jan. 1, 2015

The results of this process are illustrated in Figure 5.10, which shows a granitic rock in which some of the biotite and amphibole have been altered to form the iron oxide mineral limonite.

From Textbooks ● Jan. 1, 2015

Exceptions to this sequence are unusual; sometimes the first of the felspars have preceded the hornblende or biotite which may envelop them in ophitic manner.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" by Various

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