feldspar
any of a group of minerals, principally aluminosilicates of potassium, sodium, and calcium, characterized by two cleavages at nearly right angles: one of the most important constituents of igneous rocks.
Origin of feldspar
1- Also felspar.
Words Nearby feldspar
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use feldspar in a sentence
Sienite and feldspar succeeded in our descent to the snow line, where we found a felspathic granite.
The Life of Kit Carson | Edward S. EllisThe feldspar exhibited its splendent black crystals in fine relief in the massy quartz.
Summary Narrative of an Exploratory Expedition to the Sources of the Mississippi River, in 1820 | Henry Rowe SchoolcraftWhat little feldspar there was is reduced to quartz and mica, and the quartz pebbles are drawn out into lenses.
This was materially assisted by the weak lath shapes of the feldspar and the mobility of the micas.
The appearance of the rock is not modified by the amount of feldspar which it contains.
British Dictionary definitions for feldspar
felspar
/ (ˈfɛldˌspɑː, ˈfɛlˌspɑː) /
any of a group of hard rock-forming minerals consisting of aluminium silicates of potassium, sodium, calcium, or barium: the principal constituents of igneous rocks. The group includes orthoclase, microcline, and the plagioclase minerals
Origin of feldspar
1Derived forms of feldspar
- feldspathic (fɛldˈspæθɪk, fɛlˈspæθ-), felspathic, feldspathose or felspathose, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for feldspar
[ fĕld′spär′, fĕl′- ]
Any of a group of abundant monoclinic or triclinic minerals having the general formula MAl(Al,Si)3O8, where M is either potassium (K), sodium (Na), or calcium (Ca) or less commonly barium (Ba), rubidium (Rb), strontium (Sr), or iron (Fe). Feldspars range from white, pink, or brown to grayish blue in color. They occur in igneous, sedimentary, and metamorphic rocks and make up more than 60 percent of the Earth's crust. When they decompose, feldspars form clay or the mineral kaolinite.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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