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Related to microcline: sanidine, orthoclase


see feldsparfeldspar
or felspar
, an abundant group of rock-forming minerals which constitute 60% of the earth's crust. Chemically the feldspars are silicates of aluminum, containing sodium, potassium, iron, calcium, or barium or combinations of these elements.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a mineral of the feldspar group. It is a triclinic K-Na feldspar with the chemical composition (K, NaXAlSiaOg]; it contains negligible quantities of Ca, Ba, Fe, Rb, and Cs. Microcline often forms perthites, which are microclines with small albite intergrowths. It occurs as individual grains, grain aggregates, prismatic crystals, or single crystals with a volume up to several m3. The mineral has a hardness of 6–6.5 on Mohs’ scale and a density of 2,540–2,570 kg/m3. It may be pink, brownish yellow, reddish white, or pinkish red; less frequently it is white or bluish green (amazonite, or amazonstone). Microcline has a vitreous or pearly luster. A thin section of the mineral under the microscope shows multiple twins, forming the characteristic microclinic grating structure.

Microcline is a typical rock-forming mineral contained in granite, granodiorite (syenite), pegmatite, and gneiss. It is the primary raw material used by the ceramics industry (porcelain, glazed pottery, and industrial ceramics). Amazonite is used as an ornamental stone.


Kostov, I. Mineralogiia. Moscow, 1971. (Translated from English.)
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


KAlSi3O8 A triclinic potassium-rich feldspar, usually containing minor amounts of sodium; may be clear, white, pale-yellow, brick-red, or green, and is generally characterized by crosshatch twinning.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Mos: muscovite; Kao: kaolinite; Qz: quartz; Cor: corundum; Mic: microcline; Hem: Hematite; An: anorthite; Cal: Calcite.
Moreover, microcline and calcium feldspar levels increased from 0.039 to 0.081 when the heating rate rose from 30[degrees]C/min to 40[degrees]C/min, and, at 50[degrees]C/min heating rate, the two components increased to 0.49.
Among the feldspars, K-feldspar grains predominated over alkaline ones, and orthoclase crystals over the microcline variety.
The geology of the area mapped consist of three rock types namely banded gneiss and granite gneiss with pegmatite intruding into the older lithologies of rock deposits within the Ijero study area, thin section studies reveals quartz, plagioclase, microcline, biotite, and opaque minerals as the main mineral constituents.
Minor constituent 307 Smectite + vermiculite 259 Albite + microcline 263 Muscovite + illite + kaolinite 261 279 Albite + microcline + muscovite + illite 291 S1 Muscovite + illite S3 Hornblende (riebeckite) S4 Chlorite + muscovite + illite S9 S11 Albite + microcline S12 Muscovite + illite + kaolinite S13 255 Muscovite + illite + kaolinite 267 Muscovite + illite + kaolinite 273 288 303 Muscovite + illite S/No.
2002) and potassium from biotite and microcline (Wallander and Wickman, 1999).
XRD analysis revealed that Sevier Shale is composed of quartz, orthoclase, microcline, calcite, gypsum, chlorite, illite, and mixed layers of kaolinitemontmorillonite (Fig.
Finally, Luis had matrix specimens in miniature to small-cabinet sizes showing brown, gemmy eosphorite crystals to 1 cm on microcline. An added bonus were olive-green hemispherical clusters (to 4 mm) of greifensteinite microcrystals scattered on matrix.
Using mineral phase equilibria diagrams, he showed that the majority of bore water analyses from known Pilliga Sandstone aquifers fell within the kaolinite field, and concluded that minerals such as microcline or biotite mica would be chemically unstable when in contact with such water and tend to alter to kaolinite.
The feldspar fraction is dominantly altered orthoclase feldspar and perthitic ortho-clase feldspar with traces of microcline and plagioclase.
granite: A common, coarse-grained, light-colored, hard igneous rock consisting chiefly of quartz, orthoclase or microcline, and mica; very dense and nonporous.