Feldspar
Feldspar Feld"spar`, Feldspath Feld"spath`, n. [G. feldspath; feld field + spath spar.] (Min.) A name given to a group of minerals, closely related in crystalline form, and all silicates of alumina with either potash, soda, lime, or, in one case, baryta. They occur in crystals and crystalline masses, vitreous in luster, and breaking rather easily in two directions at right angles to each other, or nearly so. The colors are usually white or nearly white, flesh-red, bluish, or greenish. [1913 Webster]

Note: The group includes the monoclinic (orthoclastic) species orthoclase or common potash feldspar, and the rare hyalophane or baryta feldspar; also the triclinic species (called in general plagioclase) microcline, like orthoclase a potash feldspar; anorthite or lime feldspar; albite or soda feldspar; also intermediate between the last two species, labradorite, andesine, oligoclase, containing both lime and soda in varying amounts. The feldspars are essential constituents of nearly all crystalline rocks, as granite, gneiss, mica, slate, most kinds of basalt and trachyte, etc. The decomposition of feldspar has yielded a large part of the clay of the soil, also the mineral kaolin, an essential material in the making of fine pottery. Common feldspar is itself largely used for the same purpose.


The Collaborative International Dictionary of English. 2000.

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  • Feldspar — is the name of a group of rock forming minerals which make up as much as 60% of the Earth s crust.Feldspar. [http://www.ima na.org/about industrial minerals/feldspar.asp What is Feldspar?] Industrial Minerals Association. Retrieved on July 18… …   Wikipedia

  • feldspar — 1785, earlier feldspath (1757), from Ger. Feldspath (Mod.Ger. Feldspat), from Feld field (see FIELD (Cf. field) (n.)) + spath spar, non metallic mineral, gypsum (see SPAR (Cf. spar) (n.2)); spelling influenced by English spar …   Etymology dictionary

  • feldspar — (also felspar) ► NOUN ▪ a pale rock forming silicate mineral. ORIGIN German Feldspat field spar …   English terms dictionary

  • feldspar — [feld′spär΄] n. [altered < Ger feldspath (now feldspat) < feld, FIELD + spath, spar < IE base * spe , long, flat board > SPOON, SPADE1] any of several light colored, hard, glassy, monoclinic or triclinic minerals made up of aluminum… …   English World dictionary

  • feldspar — /feld spahr , fel /, n. 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. Also, felspar.… …   Universalium

  • feldspar — noun Etymology: modification of obsolete German Feldspath (now Feldspat), from German Feld field + obsolete German Spath (now Spat) spar Date: 1772 any of a group of crystalline minerals that consist of aluminum silicates with either potassium,… …   New Collegiate Dictionary

  • feldspar — noun Any of a large group of rock forming minerals that, together, make up about 60% of the earths outer crust. The feldspars are all aluminum silicates of the alkali metals sodium, potassium, calcium and barium. Feldspars are the principal… …   Wiktionary

  • feldspar —   the generic name for a group of minerals made up of aluminium silicate along with calcium, potassium or sodium. A component of granite …   Geography glossary

  • feldspar — feld|spar [ˈfeldspa: US a:r] n [U] [Date: 1700 1800; : German; Origin: feldspath, from feld field + spath type of mineral] a type of grey or white mineral …   Dictionary of contemporary English

  • feldspar — feld|spar [ fel,spar ] noun uncount a type of hard pale stone …   Usage of the words and phrases in modern English

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