orthoclase

[ awr-thuh-kleys, -kleyz ]

/ ˈɔr θəˌkleɪs, -ˌkleɪz /

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noun

a common white or pink mineral of the feldspar group, KAlSi3O8, having two good cleavages at right angles, and found in silica-rich igneous rocks: used in the manufacture of porcelain.

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Origin of orthoclase

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

Words nearby orthoclase

orthoboric acid, orthocenter, orthocentre, orthocephalic, orthochromatic, orthoclase, orthoclastic, ortho-cousin, ortho-dichlorobenzene, orthodontia, orthodontics

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use orthoclase in a sentence

There is also some variation in the amount of quartz present, and in the relative importance of the orthoclase and plagioclase.
Mount Rainier|Various
Orthoclase becomes a clear glass filled with bubbles: at a lower temperature beryl behaves in the same way.
Scientific American Supplement, Vol. XXI., No. 531, March 6, 1886|Various
It often occurs as a constituent of granite, not unfrequently being associated in the same rock with pink felspar or orthoclase.
Geology|James Geikie
Sanidine, san′i-din, n. a clear glassy variety of orthoclase.
Chambers's Twentieth Century Dictionary (part 4 of 4: S-Z and supplements)|Various

Vogesites contain hornblende and orthoclase; spessartites, hornblende and plagioclase.
Encyclopaedia Britannica, 11th Edition, Volume 16, Slice 2|Various

British Dictionary definitions for orthoclase

orthoclase

/ (ˈɔːθəʊˌkleɪs, -ˌkleɪz) /

noun

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

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for orthoclase

orthoclase

[ ôr′thə-klās′ ]

A white to yellowish red monoclinic mineral of the potassium feldspar group that forms from medium- to low-temperature magmas. Chemical formula: KAlSi3O8.