Orthoclase
/ˈɔːr.θəˌkleɪs/noun
A common rock-forming feldspar mineral, usually pink, white, or gray, found in igneous rocks.
Did you know?Orthoclase was named from Greek roots because it cleaves in two directions at nearly right angles, a precise crystal habit that made early mineralogists think in terms of geometry almost like sacred architecture.
Etymological Timeline
Ancient Greek
Greek
orthós
“straight, upright”
Ancient Greek
Greek
klân
“to break, cleave”
1820s
German/French scientific
Orthoklas
“a feldspar distinguished by its straight-angle cleavage”
19th Century
English
orthoclase
“a feldspar mineral with cleavage at near-right angles”
Modern English
English
orthoclase
“a common potassium feldspar mineral”
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