oligoclase

[ 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.

Nearby words

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

Amelia Court House, Virginia, is another locality whence come pieces either of orthoclase or oligoclase exhibiting this property.
Birds and Nature, Vol. 12 No. 2 [July 1902]|Various
At Danbury the mineral occurs with microcline and oligoclase embedded in dolomite.
Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 9|Various
These intermediate members are the lime-soda felspars known as oligoclase, andesine, labradorite and bytownite.
Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 2|Various
The felspar ranges from bytownite to oligoclase, being usually a variety of labradorite; orthoclase is scarce.
Encyclopaedia Britannica, 11th Edition, Volume 16, Slice 5|Various

The felspar of the granulites is mostly orthoclase or cryptoperthite; microcline, oligoclase and albite are also common.
Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3|Various

British Dictionary definitions for oligoclase

oligoclase

/ (ˈɒlɪɡəʊˌkleɪs) /

noun

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

oligoclase

[ ŏl′ĭ-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.