oligoclase

American  

[ol-i-goh-kleys] / 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

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

A variety of translucent quartz, spangled throughout with scales of yellow mica. ÷ feldspar, a variety of oligoclase with internal firelike reflections due to the presence of minute crystals, probably of hematite; sunstone.

From Webster's Unabridged Dictionary (2nd 100 Pages) by Noah Webster

The accessory minerals of these rocks are principally oligoclase, muscovite, apatite and zircon.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" by Various

These intermediate members are the lime-soda felspars known as oligoclase, andesine, labradorite and bytownite.

From Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 2 "Fairbanks, Erastus" to "Fens" 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