microcline


microcline
/muy"kreuh kluyn'/, n.
a mineral of the feldspar group, potassium aluminum silicate, KAlSi3O8, identical in composition with orthoclase but having triclinic instead of monoclinic crystals, used in making porcelain.
[1840-50; MICRO- + -cline < Gk klínein to LEAN1, referring to the angles between its cleavage planes, which differ slightly from 90°]

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Common feldspar mineral, one form of potassium aluminosilicate (KAlSi3O8) that occurs in many rock types.

Green specimens are called amazonstone and may be used as gems. It is an end-member composition in the alkali feldspar series. See also orthoclase.

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      a common feldspar mineral, one form of potassium aluminosilicate (KAlSi3O8) that occurs in igneous rock. Green specimens are called amazonstone, which is sometimes used as a gem. Microcline forms multiple-twinned crystals and two sets of fine, tapering lamellae at right angles to each other; this tartan twinning distinguishes it from other feldspars. Microcline is found at Baveno, Italy; Kragerø, Nor.; Madagascar; and, as amazonstone, in the Urals, Russia, and Florissant, Colo., U.S. For detailed physical properties, see feldspar (table).

      Microcline is the form of potassium feldspar that is stable at the lowest temperatures. Its structure differs from that of orthoclase because of a different distribution of silicon and aluminum atoms in its aluminosilicate crystal framework. Microcline exhibits a variation in symmetry. Individual specimens range from those that are triclinic (triclinic system) (three unequal axes inclined obliquely to one another) to those that are barely distinguishable from monoclinic (monoclinic system) (three unequal axes, only one of which is inclined obliquely).

      Microcline forms a series of mixtures with the plagioclase albite, the sodium atoms of which replace the potassium atoms in the microcline structure. The intermediate members of the series are called microcline–microperthites and exhibit exsolution (separation) of the sodium and potassium phases into minute intergrowths of distinct crystals of the pure compounds. It has been suggested that this chemical variation might also influence the symmetry.

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Universalium. 2010.

Look at other dictionaries:

  • Microcline — Microcline[1] Catégorie IX : silicates[2] …   Wikipédia en Français

  • microcline — ● microcline nom masculin Feldspath triclinique potassique, que l on trouve dans les granites et les gneiss. microcline [mikʀoklin] n. f. ÉTYM. 1897; de micro , et du grec klinein « incliner ». ❖ ♦ Minér. Feldspath potassique ou sodique …   Encyclopédie Universelle

  • Microcline — Mi cro*cline, n. [Micro + Gr. ? to incline.] (Min.) A mineral of the feldspar group, like orthoclase or common feldspar in composition, but triclinic in form. [1913 Webster] …   The Collaborative International Dictionary of English

  • microcline — [mī′krō klīn΄] n. [Ger mikroklin (< Gr mikros, small + klinein, to incline: see LEAN1): its cleavage angle differs slightly from 90°] a triclinic feldspar, KAlSi3O8, that is dimorphic with orthoclase; potassium aluminum silicate …   English World dictionary

  • Microcline — Optical properties Microcline Microcline feldspar Crystal System: Triclinic Color in PPL …   Wikipedia

  • microcline — noun A common feldspar of igneous, plutonic, and metamorphic rocks, made of potassium aluminum silicate, with the chemical formula KAlSiO. Microcline is the main feldspar of granite. The bluish green variety is called amazonstone, and is… …   Wiktionary

  • microcline — (entrée créée par le supplément) (mi kro kli n ) adj. Terme de cristallographie. Qui a de petites inclinaisons. •   Sur le feldspath microcline, CH. STE CLAIRE DEVILLE Acad. des sc. Comptes rend. t. LXXXII, p. 1015. ÉTYMOLOGIE    Du grec, petit,… …   Dictionnaire de la Langue Française d'Émile Littré

  • microcline — mikroklinas statusas T sritis chemija apibrėžtis Triklininis natrio putnagas. formulė (K,Na)[AlSi₃O₈] atitikmenys: angl. microcline rus. микроклин …   Chemijos terminų aiškinamasis žodynas

  • microcline — noun Etymology: German Mikroklin, from mikr micr + Greek klinein to lean more at lean Date: 1849 a triclinic mineral of the feldspar group that is like orthoclase in composition …   New Collegiate Dictionary

  • microcline — [ mʌɪkrə(ʊ)klʌɪn] noun a green, pink or brown mineral consisting of potassium rich feldspar. Origin C19: from Ger. Microklin, from Gk mikros small + klinein to lean (because its angle of cleavage is close to 90 degrees) …   English new terms dictionary


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