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

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 Project Gutenberg

Sanidine, san′i-din, n. a clear glassy variety of orthoclase.

From Project Gutenberg

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 Project Gutenberg

The best developed crystals are those which accompany mica, augite, sanidine, &c., in the ejected blocks of metamorphosed limestone from Monte Somma, the ancient portion of Mount Vesuvius; these are perfectly colourless and transparent, and are bounded by numerous brilliant faces.

From Project Gutenberg