adularia


adularia
/aj'euh lair"ee euh/, n. Mineral.
a sometimes opalescent variety of orthoclase formed at a low temperature.
[1790-1800; < It < F adulaire, named after Adula a mountain group in Switzerland; see -ARY]

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      a feldspar mineral and potassium aluminosilicate (KAlSi3O8). It commonly forms colourless, glassy, prismatic, twinned crystals in low-temperature veins of felsic plutonic rocks and in cavities in crystalline schists. Typical occurrences include the schists of the Alps. Some adularia show an opalescent play of colours and are called moonstone.

      Adularia and orthoclase are similar, but adularia is pseudo-orthorhombic. Slight differences in refractive indices, specific gravity, temperature of their conversion to sanidine (a high-temperature form of potassium feldspar), and axial angle, however, indicate the existence of two different species.

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Universalium. 2010.

Look at other dictionaries:

  • Adularia — Ad u*la ri*a, n. [From Adula, a mountain peak in Switzerland, where fine specimens are found.] (Min.) A transparent or translucent variety of common feldspar, or orthoclase, which often shows pearly opalescent reflections; called by lapidaries… …   The Collaborative International Dictionary of English

  • Adularia — is a tectosilicate mineral with formula KAlSi3O8. It is a form of orthoclase which crystallizes at unusually low temperatures. It is found in the Adula Mountains of Switzerland. The genesis is usually hydrothermal (low temeperature alpine veins) …   Wikipedia

  • adulária — s. f. [Mineralogia] Ortosa …   Dicionário da Língua Portuguesa

  • adularia — (De Adula, montaña de Suiza). f. Geol. Variedad de feldespato, transparente y generalmente incoloro …   Diccionario de la lengua española

  • adularia — [a΄jo͞o ler′ē ə, a΄jəler′ē ə] n. [It < Fr adulaire, after Adula, a group of mountains in Switzerland + aire, ARY] a transparent or translucent variety of orthoclase …   English World dictionary

  • Adularia — ► sustantivo femenino MINERALOGÍA Mineral que pertenece al grupo de los feldespatos, transparente y generalmente incoloro. * * * adularia (de «Adula», nombre de una montaña suiza) f. Variedad de feldespato, transparente y generalmente incolora. * …   Enciclopedia Universal

  • adularia — noun A variety of orthoclase feldspar found as colorless to white prismatic crystals in cavities in metamorphic rocks. Some specimens reflect a bluish sheen along crystal faces. This phenomenon is called adularescence, and adularia with this… …   Wiktionary

  • adularia — noun Etymology: Italian, from French adulaire, from Adula, Swiss mountain group Date: 1798 a transparent or translucent orthoclase …   New Collegiate Dictionary

  • adularia — a·du·là·ria s.f. TS mineral. varietà di ortoclasio, spec. incolore, talvolta gialla o nocciola, usata come pietra ornamentale {{line}} {{/line}} DATA: 1806. ETIMO: der. di Adula, antico nome di un gruppo montuoso delle Alpi svizzere, con aria f …   Dizionario italiano

  • adularia — pl.f. adularie …   Dizionario dei sinonimi e contrari