orthoclase

American  

[awr-thuh-kleys, -kleyz] / ˈɔr θəˌkleɪs, -ˌkleɪz /

noun

1. a common white or pink mineral of the feldspar group, KAlSi 3 O 8 , having two good cleavages at right angles, and found in silica-rich igneous rocks: used in the manufacture of porcelain.

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orthoclase British  

/ ˈɔːθəʊˌkleɪs, -ˌkleɪz /

noun

1. a white to pale yellow, red, or green mineral of the feldspar group, found in igneous, sedimentary, and metamorphic rocks. It is used in the manufacture of glass and ceramics. Composition: potassium aluminium silicate. Formula: KAlSi 3 O 8 . Crystal structure: monoclinic

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orthoclase Scientific  

/ ôr′thə-klās′ /

1. A white to yellowish red monoclinic mineral of the potassium feldspar group that forms from medium- to low-temperature magmas. Chemical formula: KAlSi ₃ O ₈ .

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Etymology

Origin of orthoclase

1840–50; ortho- + -clase < Greek klásis cleavage, breaking

Example Sentences

Felsic is the compositional term applied to continental igneous minerals and rocks that contain an abundance of orthoclase feldspar.

From Textbooks • Jan. 1, 2017

At the same time orthoclase and microcline are both potassium felspars; yet the former crystallizes in the monoclinic, and the latter in the triclinic system.

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

This change may be illustrated by quoting the analysis of a kaolin clay formed by the disintegration of orthoclase felspar.

From Manures and the principles of manuring by Aikman, Charles Morton

The turbidity of orthoclase is usually due to partial kaolinization.

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

In syenite and greenstone it occurs more commonly than orthoclase.

From Geology by Geikie, James