sanidine

American  

[san-i-deen, -din] / ˈsæn ɪˌdin, -dɪn /

noun

Mineralogy.

1. a glassy, often transparent variety of orthoclase in which sodium may replace as much as 50 percent of the potassium: forms phenocrysts in some igneous rocks.

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sanidine British  

/ ˈsænɪˌdiːn, -dɪn /

noun

1. an alkali feldspar that is a high-temperature glassy form of orthoclase in flat, tabular crystals, found in lavas and dykes. Formula: KAlSi 3 O 8

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Other Word Forms

• sanidinic adjective

Etymology

Origin of sanidine

1805–15; < German Sanidin, equivalent to Greek sanid- (stem of sanís plank) + German -in -ine ²

Example Sentences

Renne, P. R., Mundil, R., Balco, G., Min, K. & Ludwig, K. R. Joint determination of 40K decay constants and 40Ar*/40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/39Ar geochronology.

From Nature • Nov. 28, 2017

Matthews, N. E., Vazquez, J. A. & Calvert, A. T. Age of the Lava Creek supereruption and magma chamber assembly at Yellowstone based on 40Ar/39Ar and U-Pb dating of sanidine and zircon crystals.

From Textbooks • Jan. 1, 2017

Trachyte from Hungary; felsitic paste with crystals of hornblende and sanidine, and a little magnetite.

From Volcanoes: Past and Present by Hull, Edward

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

Monoclinic felspar does, however, occur in some of these rocks; but the difficulty of ascertaining the precise character of microliths renders it unsafe to speculate on the amount of sanidine which may be present.

From Etna A History of the Mountain and of its Eruptions by Rodwell, G. F.