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, trā′kīt, n. a crystalline igneous rock, generally grayish in colour, usually fine-grained or compact, more or less markedly porphyritic, with large crystals of sanidine and scales of black mica.—adjs.

From Chambers's Twentieth Century Dictionary (part 4 of 4: S-Z and supplements) by Various

Twin crystal of sanidine from the lava of 1858.

From Volcanoes: Past and Present by Hull, Edward

Spherulitic structure is not infrequent; and occasionally a few crystals of sanidine, augite, or hornblende are to be seen imbedded in the glassy ground-mass.

From Volcanoes: Past and Present by Hull, Edward