andalusite

American  

[an-dl-oo-sahyt] / ˌæn dlˈu saɪt /

noun

Mineralogy.

1. an orthorhombic form of aluminum silicate, Al 2 SiO 5 , found in schistose rocks.

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andalusite British  

/ ˌændəˈluːsaɪt /

noun

1. a grey, pink, or brown hard mineral consisting of aluminium silicate in orthorhombic crystalline form. It occurs in metamorphic rocks and is used as a refractory and as a gemstone. Formula: Al 2 SiO 5

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andalusite Scientific  

/ ăn′də-lo̅o̅′sīt′ /

1. A hard, grayish white to pinkish brown orthorhombic mineral. Andalusite occurs as nearly square prisms, often with cross-shaped cross sections, in metamorphic rocks. It is a polymorph of kyanite and sillimanite, but forms at shallower depths than they do, and at higher temperatures than kyanite and lower temperatures than sillimanite. Chemical formula: Al ₂ SiO ₅ .

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Etymology

Origin of andalusite

1830–40; named after Andalusia, where it was first found; see -ite ¹

Example Sentences

Quartz is a good example as slightly different forms are stable between 0°C and 1800°C. The minerals kyanite, andalusite, and sillimanite are polymorphs with the composition Al2SiO5.

From Textbooks • Jan. 1, 2015

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

From Textbooks • Jan. 1, 2015

The andalusite may be pink and is then often pleochroic in thin sections, or it may be white with the cross-shaped dark enclosures of the matrix which are characteristic of chiastolite.

From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 6 "Home, Daniel" to "Hortensius, Quintus" by Various

Where the schists of sedimentary origin have been pierced by these igneous intrusions, they are charged with contact minerals such as sillimanite, cordierite, kyanite and andalusite.

From The Project Gutenberg Encyclopedia Volume 1 of 28 by Project Gutenberg

The sedimentary schists into which these rocks have been intruded may show contact alteration by the development of such minerals as cordierite, andalusite and sillimanite.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 2 "Gloss" to "Gordon, Charles George" by Various