dacite

American  

[day-sahyt] / ˈdeɪˌsaɪt /

noun

dacites plural

1. Geology. a gray volcanic rock similar to andesite but bearing quartz as a distinct characteristic.

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dacite Scientific  

/ dā′sīt′ /

1. A fine-grained light gray volcanic rock consisting primarily of quartz, plagioclase feldspar, and potassium feldspar, and also containing biotite, hornblende, or pyroxene. It is the fine-grained equivalent of granodiorite.

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Other Word Forms

• dacitic
  adjective

Example Sentences

Eichelberger, J. C. Origin of andesite and dacite: evidence of mixing at Glass Mountain in California and at other circum-Pacific volcanoes.

From Nature • Dec. 12, 2017

I. Phase equilibria and pre-eruption P-T-fO2-fH2O conditions of the dacite magma.

From Nature • Dec. 12, 2017

Chunks of juvenile gray dacite fell like hail, some as large as golf balls.

From Scientific American • Jan. 24, 2013

Released from confining pressure, gasses within the thick dacite magma came out of solution and blew through upper slump block as it fell.

From Scientific American • Aug. 9, 2012

All this gossan and porphyry, and that copper stain up there–and just look at that dacite cap!”

From Silver and Gold A Story of Luck and Love in a Western Mining Camp by Coolidge, Dane