Definition of "felsic" [felsic]

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

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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