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.

Nearby words

Also felspar.

Origin of feldspar

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

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for feldspar

Feldspar particles have as wide a range of colour as quartz, but it is easy to tell the two apart.
Earth and Sky Every Child Should Know|Julia Ellen Rogers
Granite is made of quartz, feldspar, and mica, sometimes with added particles of hornblende.
Earth and Sky Every Child Should Know|Julia Ellen Rogers
The feldspar is decomposed with the resulting formation of epidote, which is quite prominent.
The Long Labrador Trail|Dillon Wallace
As a result of the decomposition of the feldspar, much clay is formed, the main substance of which is kaolin.
Geology|William J. Miller

The substances used as a bond in manufacturing wheels are kaolin, a kind of clay, and feldspar.
Electricity and Magnetism|Elisha Gray

British Dictionary definitions for feldspar

feldspar

felspar

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

Derived Formsfeldspathic (fɛldˈspæθɪk, fɛlˈspæθ-), felspathic, feldspathose or felspathose, adjective

Word Origin for feldspar

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

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

Word Origin and History for feldspar

feldspar

1785, earlier feldspath (1757), from German Feldspath (Modern German Feldspat), from Feld "field" (see field (n.)) + spath "spar, non-metallic mineral, gypsum" (see spar (n.2)); spelling influenced by English spar "mineral."

Science 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.