from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of a group of abundant rock-forming minerals occurring principally in igneous, plutonic, and some metamorphic rocks, and consisting of silicates of aluminum with potassium, sodium, calcium, and, rarely, barium. About 60 percent of the earth's outer crust is composed of feldspar.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of a large group of rock-forming minerals that, together, make up about 60% of the earth's outer crust. The feldspars are all aluminum silicates of the alkali metals sodium, potassium, calcium and barium. Feldspars are the principal constituents of igneous and plutonic rocks.
from the GNU version of the Collaborative International Dictionary of English
- n. 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.
from The Century Dictionary and Cyclopedia
- n. In mineralogy, one of a very common group of closely related minerals, all silicates of aluminium, together with either calcium, sodium, potassium, or in one case barium.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium
Partial translation of obsolete German Feldspath : Feld, field (from Middle High German veld, from Old High German feld; see pelə-2 in Indo-European roots) + Spath, spar.(American Heritage® Dictionary of the English Language, Fourth Edition)
Feld, field (from Middle High German veld, from Old High German feld) + Spath, spar (Wiktionary)