sanidine

[ san-i-deen, -din ]

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.

sanidine

/ 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

Other Words From

• san·i·din·ic [san-i-, din, -ik], adjective

Word History and Origins

Origin of sanidine¹

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

Word History and Origins

Origin of sanidine¹

C19: from German, from Greek sanis, sanidos a board

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

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

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

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