from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Containing a group of light-colored silicate minerals that occur in igneous rocks.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium.
  • n. A rock with such properties.


fel(dspar) + s(ilica) + -ic.
(American Heritage® Dictionary of the English Language, Fourth Edition)
Blend of feldspar and silica, with the suffix -ic. (Wiktionary)


  • The magma here tends to be classified as felsic, with a much higher silicone content, which is more viscous in nature and allows for more gas to be trapped within.

    Thar She Blows « worlds in a grain of sand

  • One aspect of Iceland's volcanoes of particular interest to geoscientists is that within the magmas being extruded there are small amounts of lightweight, light-colored volcanic materials known as felsic rock, which "has no reason whatsoever for being there - it's the kind of stuff found in continental crust, not ocean crust," Seaman says.

    Newswise: Latest News

  • Aaron Slate, phyllite, metasiltstone, metatuff, felsic volcanic rocks, and Virgilina Greenstone underlie Ecoregion 45c in Virginia.

    Ecoregions of Delaware, Maryland, Pennsylvania, Virginia, and West Virginia (EPA)

  • The crescent-shaped floor of the caldera teems with a network of smaller volcanic mouths, cones, domes, lava channels, dikes, lavas from light felsic flows to viscid red lavas and black obsidian blocks, ochre plains of sandy alluvial deposits and red and black volcanic ejecta, scoria, lapilli and pumice, from a long series of basaltic effusions.

    Teide National Park, Spain

  • But Teide's lava is more felsic in composition and is quiescent, complementing the other very active basaltic sites.

    Teide National Park, Spain

  • Andesite and diorite are intermediate igneous rocks that have a chemistry between mafic and felsic (silica amounts between 53 to 65%).

    Igneous rock

  • Igneous rocks derived from felsic magma contain relatively high quantities of sodium, aluminum, and potassium and are composed of more than 65% silica.

    Igneous rock

  • Geologists have classified the chemistry of igneous rocks into four basic types: felsic, intermediate, mafic, and ultramafic.

    Igneous rock

  • Rocks formed from felsic magma include granite, granodiorite, dacite, and rhyolite.

    Igneous rock

  • Gold is disseminated within a highly weathered, clay rich sequence of metamorphosed sandstone and carbonate rocks with associated basic and felsic intrusives.

    ANC Daily News Briefing


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