[ ol-i-goh-kleys ]
/ ˈɒl ɪ goʊˌkleɪs /

noun Mineralogy.

a kind of plagioclase feldspar occurring commonly in white crystals, sometimes shaded with gray, green, or red.

Origin of oligoclase

First recorded in 1825–35; oligo- + -clase
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for oligoclase

British Dictionary definitions for oligoclase


/ (ˈɒlɪɡəʊˌkleɪs) /


a white, bluish, or reddish-yellow feldspar mineral of the plagioclase series, consisting of aluminium silicates of sodium and calcium. Formula: NaAlSi 3 O 8 .CaAl 2 Si 2 O 8

Word Origin for oligoclase

C19: from oligo- + -clase
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for oligoclase


[ ŏlĭ-gō-klās′, ō′lĭ- ]

A white to gray triclinic mineral of the plagioclase feldspar group. Oligoclase occurs in igneous rocks with a relatively high silica content, such as granite. Chemical formula: (Na,Ca)(Al,Si)AlSi2O8.
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