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[aj-uh-lair-ee-uh] /ˌædʒ əˈlɛər i ə/
noun, Mineralogy
a sometimes opalescent variety of orthoclase formed at a low temperature.
1790-1800; < Italian < French adulaire, named after Adula a mountain group in Switzerland; see -ary Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for adularia
  • adularia and chlorite are present in veins cutting certain shales.
  • adularia is locally altered to sericite, making the rock highly friable.
  • Source of the placers interpreted as gold-silver-adularia-quartz veins.
British Dictionary definitions for adularia


a white or colourless glassy variety of orthoclase in the form of prismatic crystals. It occurs in metamorphic rocks and is a minor gemstone. Formula: KAlSi3O8
Word Origin
C18: via Italian from French adulaire, after Adula, a group of mountains in Switzerland
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Encyclopedia Article for adularia

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.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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