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

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

Aventurine and moonstone varieties occur, though these special appearances are more usually displayed by the oligoclase and orthoclase felspars respectively.

From The Project Gutenberg Encyclopedia Volume 1 of 28 by Project Gutenberg

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

The felspar of the diorites ranges in composition from oligoclase to labradorite, and is often remarkably zonal, the external layers being more alkaline than the internal.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 5 "Dinard" to "Dodsworth" by Various

It is important to examinexxxi whether or not this is oligoclase, as on Teneriffe, Popocatepetl, and Chimborazo; or labradorite, as on Etna and Stromboli.

From Narrative of the Circumnavigation of the Globe by the Austrian Frigate Novara, Volume I (Commodore B. Von Wullerstorf-Urbair,) Undertaken by Order of the Imperial Government in the Years 1857, 1858, & 1859, Under the Immediate Auspices of His I. and R. Highness the Archduke Ferdinand Maximilian, Commander-In-Chief of the Austrian Navy. by Karl Ritter von Scherzer

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