oligoclase

American  

[ol-i-goh-klays] / ˈɒl ɪ goʊˌkleɪs /

noun

Mineralogy.

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

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oligoclase British  

/ ˈɒlɪɡəʊˌkleɪs /

noun

1. 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

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oligoclase Scientific  

/ ŏl′ĭ-gō-klās′,ō′lĭ- /

1. 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)AlSi ₂ O ₈ .

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Etymology

Origin of oligoclase

First recorded in 1825–35; oligo- + -clase

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Example Sentences

See Examples For:

oligoclase

Their felspar ranges from oligoclase to andesite and labradorite, and is often very zonal; sanidine occurs also in some dacites, and when abundant gives rise to rocks which form transitions to the rhyolites.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" by Various

At Danbury the mineral occurs with microcline and oligoclase embedded in dolomite.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 9 "Dagupan" to "David" by Various

These larger felspars have no crystalline outlines and consist of orthoclase or microcline surrounded by borders of white oligoclase.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" by Various

The felspar of the granulites is mostly orthoclase or cryptoperthite; microcline, oligoclase and albite are also common.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" by Various

Of their minerals felspar Is usually the most abundant, and is principally labradorite and bytownite, though anorthite occurs in some, while oligoclase and orthoclase have been found in others.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" by Various

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