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sanidine
[ san-i-deen, -din ]
noun
- 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
- 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
Word History and Origins
Origin of sanidine1
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.
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.
Sanidine, san′i-din, n. a clear glassy variety of orthoclase.
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.
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.
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