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A white to yellowish red monoclinic mineral of the potassium feldspar group that forms from medium- to low-temperature magmas.
[Greek ortho-, ortho- + Greek klasis, a breaking (from klān, to break).]
(Minerals) 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: KAlSi3O8. Crystal structure: monoclinic
or•tho•clase(ˈɔr θəˌkleɪs, -ˌkleɪz)
a common white or pink potassium feldspar mineral, KAlSi3O8, having two good cleavages at right angles, and found in silica-rich igneous rocks.
A type of feldspar consisting of potassium aluminum silicate. Orthoclase is typically white, pink, yellow, or brown, but it can also be colorless. It is especially common in igneous rocks.