feldspar

[ feld-spahr, fel- ]

noun

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

1750–60; feld- (<German: field) + spar³; replacing feldspath<German (Feld field + Spath spar)

Also felspar.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use feldspar in a sentence

Along with quartz and feldspars, the pyroxenes rank among the most common of all minerals.
Geology | William J. Miller
It was at this epoch that the rocks called feldspars, syenites, and porphyries appeared.
A Journey to the Centre of the Earth | Jules Verne
The feldspars are lath-shaped, often with castellated terminations.
Mount Rainier | Various
The feldspars are by far the most abundant of all minerals in the crust of the earth.
Geology | William J. Miller
The first of the Feldspars which may be mentioned as being prized as an ornamental stone is amazonstone or green feldspar.
Birds and Nature, Vol. 12 No. 2 [July 1902] | Various

British Dictionary definitions for feldspar

feldspar

felspar

/ (ˈfɛldˌspɑː, ˈfɛlˌspɑː) /

noun

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

C18: from German feldspat (h), from feld field + spat (h) spar ³

Derived 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

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.

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